In short, you can't. Remote methods do not run in the context of a web session, so they know nothing about it. If you need state, try with a stateful session bean. Be aware that Seam doesn't support remote interfaces, so you are basically on your own. Injection should work though.
That's not good... But is there any way to
simulatea Session at least during one method call? Is there any way to manipulate the Seam Session Handling manually?