EA is primarily a good tool for all sorts of UML modeling such as use case diagrams, object models, activity diagrams, state machines, just to name a few. You can also write use case descriptions and maintain there. However, i would not recomment creating large document like functional spec on EA. If your tech team is using Clear Case VOBS for code streams, then you should probably create a document VOB and maintain your large requirement docs there on CC.

But of course, there is a manual sync that needs to be done between your UML models that you maintain on EA and the functional specs that you maintain on CC.

I have not used and am not aware of any automated tools that will automatically sync your UML models with your text docs unless it is use case model on Rose and use case description in Requisitepro. I would like to hear and learn from other members on this automated synchronization tools.