The solution was to use the action helper flashMessenger. Initialize the helper in the controller's init, set the message in one action and retrieve it in another.
All in the manual, of course, but I had to wade through alot of stuff to finally get to it... ugh.

**Erm... as a side note... this seems like a pretty slow forum when an easy question gets answered by the author a week after posting. Oh well... I got some good feedback on this issue over at Web Design Forums - List all forums. Those stuck with untouched questions here may prefer that forum. I now do.