After Dark writes:

Do I need to do a cast or something like that to make this? Because the parameter is an object, but zope treats like a string. <dtml-in "REQUEST['parametro'].objectValues()"> Although not impossible, it is very unlikely that "REQUEST['parametro']" is itself an object. Almost surely, it is the name of an object (not the object itself).

Whenever you have an expression that evaluates to an object name (in your case "REQUEST['parametro']"), you can use the function "_.getitem" to turn the name into the corresponding object. In your case: <dtml-in "_.getitem(REQUEST['parametro']).objectValues()"> More details: "Name lookup" section of URL:http://www.dieter.handshake.de/pyprojects/zope/book/chap3.html Dieter