urlpath_regex doesn't match

["Marco Berizzi" <pupilla@xxxxxxxxxxx>]

Hi.
I'm blocking download of .wmv files with acl urlpath_regex,
but, for example, this wmv isn't catched by this rule:

http://www.gametrailers.com/download.php?id=7174&type=wmv&f=

squid.conf:
acl trojans urlpath_regex \.wmv$
http_access deny trojans

Hints?

TIA