I thought I would attack this topic next given its growing popularity in the forums !. So why is this so popular? The context is pretty much given in the earlier tutorial for creating a SOAP client.
There are at least a couple of ways for extending the given, out of the box SOAP capabilities of JIRA. Those will be writing an RPC plugin (thanks to JIRA for giving that option) and re-building the RPC plugin.
There are so many user stories for this one! How do you override some of the JIRA built in actions? How do you do some additional stuff in the JIRA built in action? Like doing some crazy things immediately after creation before the page return to the user? Or doing some innovative validations on some of those actions? Or do what is asked in this thread ?
Here is the simple answer to all those questions. Extends the JIRA actions using the webwork plugin module. There could be some alternatives in few cases (like handling it in a listener) but not always.