diff --git a/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/ExternalLaunchSupport.java b/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/ExternalLaunchSupport.java
new file mode 100644
index 00000000..8d561bd1
--- /dev/null
+++ b/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/ExternalLaunchSupport.java
@@ -0,0 +1,121 @@
+package stashpullrequestbuilder.stashpullrequestbuilder;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import hudson.model.ParameterValue;
+import hudson.model.ParametersAction;
+import hudson.model.Run;
+import stashpullrequestbuilder.stashpullrequestbuilder.stash.StashPullRequestResponseValue;
+import stashpullrequestbuilder.stashpullrequestbuilder.stash.StashPullRequestResponseValueRepository;
+
+public class ExternalLaunchSupport {
+    private static final String PULL_REQUEST_ID = "pullRequestId";
+    private static final String PULL_REQUEST_VERSION = "pullRequestVersion";
+    private static final String PULL_REQUEST_TITLE = "pullRequestTitle";
+    private static final String TARGET_BRANCH = "targetBranch";
+    private static final String DESTINATION_COMMIT_HASH = "destinationCommitHash";
+    private static final String DESTINATION_REPOSITORY_NAME = "destinationRepositoryName";
+    private static final String DESTINATION_REPOSITORY_OWNER = "destinationRepositoryOwner";
+    private static final String SOURCE_BRANCH = "sourceBranch";
+    private static final String SOURCE_COMMIT_HASH = "sourceCommitHash";
+    private static final String SOURCE_REPOSITORY_NAME = "sourceRepositoryName";
+    private static final String SOURCE_REPOSITORY_OWNER = "sourceRepositoryOwner";
+
+    private static Map<String, String> PULL_REQUEST_NOTIFIER_FOR_BITBUCKET_MAP = new HashMap<String, String>() {
+        {
+            put(PULL_REQUEST_ID, "PULL_REQUEST_ID");
+            put(PULL_REQUEST_TITLE, "PULL_REQUEST_TITLE");
+            put(PULL_REQUEST_VERSION, "PULL_REQUEST_VERSION");
+            put(SOURCE_BRANCH, "PULL_REQUEST_FROM_BRANCH");
+            put(SOURCE_REPOSITORY_OWNER, "PULL_REQUEST_FROM_REPO_PROJECT_KEY");
+            put(SOURCE_REPOSITORY_NAME, "PULL_REQUEST_FROM_REPO_SLUG");
+            put(SOURCE_COMMIT_HASH, "PULL_REQUEST_FROM_HASH");
+            put(TARGET_BRANCH, "PULL_REQUEST_TO_BRANCH");
+            put(DESTINATION_REPOSITORY_OWNER, "PULL_REQUEST_TO_REPO_PROJECT_KEY");
+            put(DESTINATION_REPOSITORY_NAME, "PULL_REQUEST_TO_REPO_SLUG");
+            put(DESTINATION_COMMIT_HASH, "PULL_REQUEST_TO_HASH");
+        }
+    };
+
+    private static Map<String, String> STASH_PULLREQUEST_BUILDER_PLUGIN_MAP = new HashMap<String, String>() {
+        {
+            put(PULL_REQUEST_ID, PULL_REQUEST_ID);
+            put(PULL_REQUEST_TITLE, PULL_REQUEST_TITLE);
+            put(PULL_REQUEST_VERSION, PULL_REQUEST_VERSION);
+            put(SOURCE_BRANCH, SOURCE_BRANCH);
+            put(SOURCE_REPOSITORY_OWNER, SOURCE_REPOSITORY_OWNER);
+            put(SOURCE_REPOSITORY_NAME, SOURCE_REPOSITORY_NAME);
+            put(SOURCE_COMMIT_HASH, SOURCE_COMMIT_HASH);
+            put(TARGET_BRANCH, TARGET_BRANCH);
+            put(DESTINATION_REPOSITORY_OWNER, DESTINATION_REPOSITORY_OWNER);
+            put(DESTINATION_REPOSITORY_NAME, DESTINATION_REPOSITORY_NAME);
+            put(DESTINATION_COMMIT_HASH, DESTINATION_COMMIT_HASH);
+        }
+    };
+
+    private static String getStringVariableValue(ParametersAction parametersAction, Map<String, String> keymap, String key) {
+        ParameterValue value = parametersAction.getParameter(keymap.get(key));
+        return value == null || value.getValue() == null ? null : value.getValue().toString();
+    }
+
+    public static StashCause resolveOnStartedStashCause(final StashCause cause, final StashRepository repository,
+                                                        final StashBuildTrigger trigger,
+                                                        final Run<?, ?> run) {
+        if (cause != null)
+            return cause;
+
+        ParametersAction parametersAction = run.getAction(ParametersAction.class);
+        if (parametersAction==null)
+            return null;
+
+        final Map<String, String> keymap;
+        if (getStringVariableValue(parametersAction,
+                STASH_PULLREQUEST_BUILDER_PLUGIN_MAP,
+                DESTINATION_COMMIT_HASH) != null) {
+            keymap = STASH_PULLREQUEST_BUILDER_PLUGIN_MAP;
+        } else if (getStringVariableValue(parametersAction,
+                PULL_REQUEST_NOTIFIER_FOR_BITBUCKET_MAP,
+                DESTINATION_COMMIT_HASH) != null) {
+            keymap = PULL_REQUEST_NOTIFIER_FOR_BITBUCKET_MAP;
+        } else
+            return null;
+
+        StashPullRequestResponseValue pullRequest = new StashPullRequestResponseValue();
+        pullRequest.setToRef(new StashPullRequestResponseValueRepository());
+        pullRequest.getToRef()
+                .setLatestCommit(getStringVariableValue(parametersAction, keymap, DESTINATION_COMMIT_HASH));
+        pullRequest.setFromRef(new StashPullRequestResponseValueRepository());
+        pullRequest.getFromRef().setLatestCommit(getStringVariableValue(parametersAction, keymap, SOURCE_COMMIT_HASH));
+        pullRequest.setId(getStringVariableValue(parametersAction, keymap, PULL_REQUEST_ID));
+        repository.init();
+        String commentId = repository.postBuildStartCommentTo(pullRequest);
+
+        StashCause newCause = new StashCause(trigger.getStashHost(),
+                getStringVariableValue(parametersAction, keymap, SOURCE_BRANCH),
+                getStringVariableValue(parametersAction, keymap, TARGET_BRANCH),
+                getStringVariableValue(parametersAction, keymap, SOURCE_REPOSITORY_OWNER),
+                getStringVariableValue(parametersAction, keymap, SOURCE_REPOSITORY_NAME),
+                getStringVariableValue(parametersAction, keymap, PULL_REQUEST_ID),
+                getStringVariableValue(parametersAction, keymap, DESTINATION_REPOSITORY_OWNER),
+                getStringVariableValue(parametersAction, keymap, DESTINATION_REPOSITORY_NAME),
+                getStringVariableValue(parametersAction, keymap, PULL_REQUEST_TITLE),
+                getStringVariableValue(parametersAction, keymap, SOURCE_COMMIT_HASH),
+                getStringVariableValue(parametersAction, keymap, DESTINATION_COMMIT_HASH),
+                commentId,
+                getStringVariableValue(parametersAction, keymap, PULL_REQUEST_VERSION),
+                new HashMap<String, String>());
+
+        run.addAction(new StashCauseWrapperAction(newCause));
+
+        return newCause;
+    }
+
+    public static StashCause resolveOnCompletedStashCause(final StashCause cause, final Run<?, ?> run) {
+        if (cause != null)
+            return cause;
+        StashCauseWrapperAction causeWrapperAction = run.getAction(StashCauseWrapperAction.class);
+        return causeWrapperAction == null ? cause : causeWrapperAction.getStashCause();
+    }
+
+}
diff --git a/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/StashBuilds.java b/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/StashBuilds.java
index ca015277..e1431a52 100644
--- a/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/StashBuilds.java
+++ b/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/StashBuilds.java
@@ -1,6 +1,9 @@
 package stashpullrequestbuilder.stashpullrequestbuilder;
 
+import hudson.EnvVars;
 import hudson.model.Cause;
+import hudson.model.ParameterValue;
+import hudson.model.ParametersAction;
 import hudson.model.Result;
 import hudson.model.Run;
 import hudson.model.TaskListener;
@@ -32,7 +35,7 @@ public StashCause getCause(Run run) {
     }
 
     public void onStarted(Run run) {
-        StashCause cause = this.getCause(run);
+        StashCause cause = ExternalLaunchSupport.resolveOnStartedStashCause(this.getCause(run), repository, trigger, run);
         if (cause == null) {
             return;
         }
@@ -44,7 +47,7 @@ public void onStarted(Run run) {
     }
 
     public void onCompleted(Run run, TaskListener listener) {
-        StashCause cause = this.getCause(run);
+        StashCause cause = ExternalLaunchSupport.resolveOnCompletedStashCause(this.getCause(run), run);
         if (cause == null) {
             return;
         }
diff --git a/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/StashCauseWrapperAction.java b/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/StashCauseWrapperAction.java
new file mode 100644
index 00000000..40fc69c7
--- /dev/null
+++ b/src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/StashCauseWrapperAction.java
@@ -0,0 +1,16 @@
+package stashpullrequestbuilder.stashpullrequestbuilder;
+
+import hudson.model.InvisibleAction;
+
+public class StashCauseWrapperAction extends InvisibleAction {
+    private final StashCause stashCause;
+
+    public StashCauseWrapperAction(StashCause stashCause) {
+        this.stashCause = stashCause;
+    }
+
+    public StashCause getStashCause() {
+        return this.stashCause;
+    }
+    
+}