Did a quick google search on this and found a couple of this.
Seam Doco is a good place to start. Here you can see something like this might do what you want.
<h:commandLink action="main" value="Exit"> <s:conversationPropagation type="none"/> </h:commandLink>
By embedding the
tag in your buttons and links you should be able to stop the conversationId from appearing (I think, not tested :P)
Alternativly this topic has been discussed on the forum a few times like