Testing across multiple sessions in merb using webrat

Question

I want to test across multiple sessions using webrat in merb. Apparently, this is fairly easy to accomodate in Rails via: http://erikonrails.snowedin.net/?p=159.

Following the same logic, I am trying to do something that follows that pattern for merb and webrat. Here is an attempt (which does not work because MerbAdapter does not respond to visit and other webrat session methods; I don't want to take too much more time with this so I have stopped here for now):

# defined in test.rb environment file
module Merb #:nodoc:
  module Test #:nodoc:
    module RequestHelper #:nodoc:
      def in_a_separate_session
        old = @_webrat_session.response.clone
        @_webrat_session = Webrat::MerbAdapter.new
        yield
        @_webrat_session.response = old
      end
    end
  end
end

I tried a few other ideas, but obviously I am missing something. Anyone else know how this would be done in merb? I think I could specify a cookie jar using the request mock, but I prefer to do this with webrat.