Vista RC1 and XP Home

I have Windows RC1 Ultimate on a laptop and XP Home on a desktop. On the XP
system, I can see folders shared by vista. I can only partially see folders
shared by XP in Vista. If i know the name of the folder and go to it
directly, I have access. However if I just try to explore the computer from
the workgroup, it says I don't have sufficient privlidges to acces it. I
turned off the firewall on both computers, disabled TCP/IP v6. I have file
and printer sharing enabled on both computers. Both computers have the guest
account activated. I am able to ping the sytem both by name and ip address.
The laptop Vista laptop is wireless if that matters. I want to be able to
sahre files both ways. Also, I need to be able to access the XP system to
use the printer. Thanks.