Sessions and GET (CGI.rb)

Hi!

I'm close to the deadline for a (rails) project that must support users without cookies. Unfortunately, there's a bug in Rails/CGI.rb, that prevents a session from propagating if:
  a) the session id is in the GET request
  b) a form has been POSTed

Now, what I'm looking for is a quick hack, that allows me to manually set the session id.

I tried something overwriting the session object using this:

session = CGI::Session.new(CGI.new, :session_id => params[:_session_id]) if(params[:_session_id])

Unfortunately that doesn't work. A new session is created, and the session.session_id differs from params[:_session_id].

What am I doing wrong? How can I recreate a session object if I know the sessions' ID?

Thanks a bunch,
Rob