[Zope] DTML call, form vars, submits

Hello, Any help with the following questions appreciated: 1. I am currently calling the SQL session product with the following code: <dtml-call "SESSION.set('user_id',per_cpk)"> I would like to change this to include a variable, like so: <dtml-call "SESSION.set('user_id',<dtml-var per_coldid>)"> but I cannot nest the the var tag inside a call tag. Is there some other way to do this? Do I have to use form variables or constants in a call? 2. Is it possible to explicitly store a value in a form variable without a submit? 3. What is the best/easiest way to force a submit? I tried calling document.submit, but I don't think I am doing it right. Thanks! Dale