Netscreen 5GT Blocking Instant messengers

[1Zeus]

I am trying to block Yahoo & MS Instant Messengers on my Netscreen 5GT router. I have 2 policies created. 1 for blocking yahoo, and the other for blocking MS IM. I created test accounts for myself. After impleting the policies for the above, it takes longer to connect; but they still connect. This is driving me nuts. Does anybody have any suggestions, or IPs that I am missing to block?

gateway.messenger.hotmail.com
207.68.172.247/32
65.54.229.248/32
63.110.132.163/32
207.68.171.245/32
207.46.110.254/32
207.46.104.20/32
65.54.228.224/32
208.172.13.253/32
64.41.192.106/32
207.46.106.120/32
206.65.183.110/32
65.54.140.158/32

scs.yahoo.com scs.yahoo.com
66.163.175.128/32
66.163.175.128/32
cs27.msg.dcn.yahoo.com
204.71.200.37/32
208.187.212.152/32
66.163.172.117/32
216.155.193.160/32
216.155.193.131/32
216.109.116.191/32
216.155.193.183/32
216.136.227.20/32
216.155.193.183/32
216.136.131.64/32
insider1.msg.vip.sc5.yahoo.com
204.71.200.36/32