[Zope] DTML call, form vars, submits

[Dale Kiefling]

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