You can create an Opaque Action through an Activity Diagram or a Modeler pane.
To create an opaque action through an activity diagram:
1. On the Activity Diagram toolbar, click the Opaque Action toolbar button, and then on the Activity Diagram click in free space or within an Activity Partition, Interruptible Activity Region or Structured Activity Node.
2. Type the name of the Opaque Action, and then press the Enter key.
To create an opaque action through a Modeler pane:
1. In a Modeler pane, right-click the Activity or Structure Activity Node that is to own the Opaque Action, point to New, point to Action Node, and then click Opaque Action.
2. Type the name of the Opaque Action, and then press the Enter key.