yahoo messenger within yahoo mail blocking

[vsam]

I know this question is not purely related to wingate, but i will appreciate any help on this
I am using wingate, and also have Puresight
I need to block yahoo chat WITHIN yahoo email (not through yahoo messenger)
its easy to block yahoo chat WITHIN the "Yahoo Mail Classic" interface, but if you switch to "Yahoo All-out mail" yahoo interface - i find it impossible to block yahoo chat, i tried everything
could anybody please help me, what port/url to block in wingate?
if i tried to block port 5050, yahoo is finding another port 80 etc. to use yahoo chat

ps: i have successfully blocked Gmail CHAT within Gmail , just block "chatenabled.mail.google.com" and it works good

[eric]

I would like to know more about on how we could do this. Thanks.

[sawi]

try to block using :
User > system policies > everyone > ban list > add any url contains : msg.yahoo.com