[Zope] ZSQL Method & AUTHENTICATED_USER

Hi, I'm trying to perform a simple MySQL lookup based on the AUTHENTICATED_USER. When I test the ZSQL method from the management interface, everything works fine. However, when I try to call the method from a DTML document, [it] returns nothing. Is this a namespace issue? I'm stumped and hoping that I'm not staring right past the problem. Can anyone point out what it is I am doing wrong? Thanks, a) DTML Document : foo <dtml-with people> <dtml-in lookup_by_username> <dtml-var "username"> </dtml-in> </dtml-with> b) ZSQL Method : people.lookup_by_username select * from people where username = "<dtml-var "REQUEST.AUTHENTICATED_USER.getUserName()">"