In the Harmony Deskbook there are ActorPins that send events which trigger certain actions in an activity diagram. If I am using UML 2.0, is there a way to model this?
First, actor pins are a Rhapsody-specific enhancement that is meant to address a very specific problem - namely, the automatic construction of sequence diagrams from activity diagrams. The idea is to mark some actions as from from or going to actors, so that when the SE Toolkit Generate Sequence Diagram parser runs, it can produce messages between the actor and use case lifelines. You can also create them by building a correct and executing activity diagram and capturing the message sequences as the activity diagram executes.
As to your second question, the short answer is "Yes, of course". Use Send Action and Receive Action to send or receive events. Such an activity diagram can be made to actually execute, and then sequence diagrams can be automatically captured from the execution, as mentioned above.