I am not sure about what you mean; maybe the problem is because you're referring to an ID from a *class* attribute, instead of an ID of an ezurl within a real *object*?
maybe try writing a test fetch for the ezurl of a real, test object, then do a $fetchresult|attribute(show)
seem's to refer to the "is_valid" ezurl object attribute, so I think the only way is "fetching" the ezurl object, but there is not fetch function to do this by ID (only the "list")...
