[OT] someone using jabber with yahoo transport?

[Jois]

I know I am off topic but I do not know where to ask my question:
I use Jabber client and have a yahoo messenger ID: the transport is 
yahoo.jabber.linux.it
how could I add a contact?
I connect as joislinux with my password, but how could I add a contact? for 
example bobby at yahoo.jabber.linux.it? this way it does not work
With Msn I have just username%msn.com at msn.jabber.linux.it and with ICQ it 
would be as 242977025 at icq.jabber.linux.it
for yahoo it seems not to work. some solutions?
thanks, Jois