[Zope] RESPONSE.redirect - dynamic names?

Is there some reason why the insertion of a variable into a redirect might not work? Thus: <dtml-let param="'sometext'"> -- sets param <dtml-var param> -- prints param as 'sometext' <dtml-call "RESPONSE.redirect('processform?withparam=<dtml-var param>')"> -- sends the string 'withparam=' across, missing the param value The characters making up 'sometext' are valid HTML characters. Thank you, Geoff