nimda and squid

hello, I tried to activate blocking of nimda files (*.eml) via squid. but squid did not block any elm-file. I tested it with squid coming qith suse 6.3 and with the newest swuid from suse for suse 7.0. the same config file works with the current squid on a freebsd box, and I heard that squid also works on some debian boxes. cu, Tilo