modeling chat room use cases

[go canal <go...@yahoo.com>]

Hello,
I was trying to understand how I can support chat room use cases. Need help here.

I am using Java, with Spring integration, and AjaxServlet.

What I would like to support:
 - dynamically create a chat room
   this is not a problem, since a topic is created upon receiving the first message; however,
- I also want to archive the messages at the server side. So I need to have a listener which captures all the messages to all the chat rooms

what do I need to do so that the server side listener can receive the messages to a dynamically created topic ?

I tried to create the temporary topic at the server side, but I am not able to register a listener to the new topic. What is the correct way of doing this ? Or if there are other more proper ways to model the chat room use cases ?
 appreciate any help!
thanks
canal