Problems with (routed) cross domain dfs

I have two domain (windows server 2003 enterprise edition) in the same
forest on two different classes (192.168.0.x and 192.168.1.x) with RIP2
enabled with RRAS on the two domain server (the two routing NIC are on
192.168.10.1 and 192.168.10.2). Every domain has its own DNS and the
transitive trusts relationships are working good. I tried every kind of
sharing and are all working but I cannot use the DFS.

Every time I try to access the root of the DFS in domain A from Domain B I
obtain the following message:

"xxx.xxx.xxx\root is not accessible. You might not have permission to use
this network resource. Contact the administrator of this server to find out
if you have access permissions.
Configuration information could not be read from the domain controller,
either because the machine is unavailable, or acces has been denied"

This is not an access permission problem 'cause I tried to remove DFS root
and the same share become accessible.
In addition I cannot browse the DFS root in domain A from domain B using DFS
mmc ("RPC server is unavailable"). The strange thing is that I can create a
root DFS from domain B in domain A using the same mmc console.

Anyone can help me, please?

Thanks a lot.

Riccardo