A very late reaction and maybe a lot of people figured this out themselves, but there is a simple solution that I didn't find on this forum yet:
For roaming profiles SME makes a folder in /home/e-smith/files/samba/profiles for every user.
So for user 'test' it makes the folder /home/e-smith/files/samba/profiles/test
Windows XP puts all it's profile setting etc in that map.
Windows Vista can't put it in that map.
The solution is to simply make another folder for the Vista profile named username.V2
So for the user 'test' make a new map /home/e-smith/files/samba/profiles/test.V2
Give only the owner all permissions (700) and change the owner and group to the user.
Then log on to the Vista machine and when logging of it will put the profile in this .V2 folder
The downside is offcourse that you have to make a new folder and modify the permissions for it for every user.
The good part is that it's a simple action that doesn't involve any actions on the client side.
Secondly, since it is simply a new folder in the profiles map, it should be backed up with the other profiles.