Xen 3.2.0 - domU cannot reach the internet

[mixer_ <mixer_@scurvydogs.org>]

hi, i recently updated to xen 3.2 and now networking has stopped working.
i have a configuration with 2 nics: eth1 (internet) and eth0 (lan)
when i start xend i get peth{0,1} with no ip, and xenbr{0,1} with the
right addresses
the server running xen is also the lan gw
the routing table seems ok
192.168.0.0    *                   255.255.255.0    U     0     
0        0 xenbr0
1.232.xx.0      *                   255.255.240.0    U     0     
0        0 xenbr1
default            1.232.xx.1    0.0.0.0                UG   0     
0        0 xenbr1

connections coming from the lan are all ok and the nat works well, but
the ones coming from the domUs cannot transmit any data.
the domUs are on the same subnet of dom0 (192.168.0.0/24), gw and ns are ok
i use iptables with MASQUERADE for nat and tried the NOTRACK solution
but it's not working for me
from domUs i can ping the outside if i use an ip as parameter for ping,
and when dumping traffic on dom0 i see some ACKs ..looks like the
connection is established, but no data comes back
ie.
telnet $google's_ip 80
get index.php

i get connected but i receive no data, in traffic dump i can see the
packet containing "get index.php" going out and then the connection goes
timeout
the firewall is completely empty and in ACCEPT, the only rules i used
are MASQUERADE for nat and NOTRACK in raw table

has anyone found a solution with xen 3.2?
thanks in advance for help