[Zope] Direct SQL-Method traversal

I have implemented a simple ZSQL-Method (fetch) which takes one argument, a record number (nr). As far as I understand the ZSQL Manual, I should be able to write URL's of the form fetch/nr/<number>/showit where showit is a DTML-Document which can access the result of the fetch query. How do I access this result? I tried to use the column names (like <!--#var shortname-->, where shortname is a result column name), but Zope gave me a Key Error. What is the correct syntax to access the result columns of such a query? Stefan.