[Seaside] Wrong session class used

[tblanchard at mac.com]

I'm working on the Wafer weblog clone and created a subclass of 
WAControllerSession called WaferSession - which I specified in Config 
when I created the wafer application.  In the session I add a method 
called logins that returns a dictionary.

I get a walkback because apparently self session returns a 
WAControllerSession - is this a known bug?  And is there a fix?

I'm using the b4 version I got from beta4 sometime ago.

-Todd Blanchard