Rails, Cucumber, Capybara: session is not persisted

I'm trying to write a test for a feature that relies on some session stored data and my scenario looks like this:

Scenario: Create offer
  Given I am on the start offer page
  When I select "Foo" from "bar"
  And I press "Go on"
  Then I should see "You are going to offer foo"

By using the debugger I found out, that the information is stored in the session correctly, but on every new request I get a fresh session.

Should'nt there be a working session for at least every scenario? Any ideas why this isn't the case?

Thanks in advance, Joe

Versions: Running on rails 2.3.10, cucumber 0.10.0, cucumber-rails 0.3.2, capybara 0.4.1.2