Vista and Mac

I used till yesterday the RTM Version of Vista ultimate. Tonight i've
installed Vista ultimate final, the versione came out on 01/31.

With booth versions (RTM and final) i got some problems accessing my mac. I
can ses it on the network (same workgroup) but when it asks me user name and
password, vista tells me authentication failed, and there is no way to enter
into my mac.

I don't know how but with the RTM version i solved the problem (maybe i've
changed some setting in controll pannel, how remember?),SO IT'S POSSIBLE,
but now, with this final version i got the same problem.

Anyone else had this problem and can tell me how to solve it?

thanks