Symantec AntiVirus Corporate Edition 10.2 client and server for vista

Hello everybody, I have a problem about NAV in my company about symantect, Please help me solute it. Many thanks
Now our system using Symantec AntiVirus Corporate Edition 10.2 client and server. NAV Server setup in to Window Sever 2003. And nearly all of client using windows XP. Untill now the symantec run ok,
But now we have some client setup window vista ultimate. I setup Symantec AntiVirus Corporate Edition 10.2 client (version client) into vista but the server can't see client.
I don't know how to fix it. Because now Microsoft don't sell winxp
Please help me, thanks