[Zope] force upper case in REQUEST

Hi, I want to force a property entered by a user when creating a zclass to uppercase. The _addform method for the Zclass sends a REQUEST variable 'id' to the _add method. The _add method currently does this: <!--#with "SubjectClass.createInObjectManager(REQUEST['id'], REQUEST)"--> <dtml-call "propertysheets.subject_info.manage_changeProperties( subject_code=REQUEST['id'], ... <!--#/with--> But I want the subject_code property to be uppercase, so I imagine I need something like: <!--#with "SubjectClass.createInObjectManager(REQUEST['id'], REQUEST)"--> <dtml-call "propertysheets.subject_info.manage_changeProperties( subject_code=<dtml-var id upper>, ... <!--#/with--> This returns invalid syntax? How can I convert to upper case?