[Zope] Syntax problem

All, I'm having a silly syntax problem again, and I can't get it right. I'm try to update a value in a list DetailBodyHeader at Index DetailEditSection with the value in the variable BodyText. The following statement executes without error, but doesn't update the value: dtml-call "REQUEST.set('DetailBodyHeader[DetailEditSection]',BodyHeader)" Can someone point me in the right direction? Many thanks, Jeff