NFS traffic trough pfSense 2.0R- C2

[gdavid]

Hi guys. I'm rumming pfSense 2.0-RC2 (amd64), built on Tue Jun 7 15:17:21 EDT 2011.
I'm experiencing some issue with NFS trafich passing through pfSense
The scenario is:
WAN, LAN with virtual IP. I mean, LAN has its main address in the  192.168.1.0/24 network and a Virtual IP on the 192.168.2.0/24 network.
Computer clients are on the 192.168.2.0/24 network, a TFTP and NFS server is on 192.168.1.0/24 network.
Clients boot via TFTP, then mount an NFS share from the same server (different from the pfSense)
TFTP boot is ok, NFS mount is ok, but at the very first file transfer bigger than 900kB, the client hangs. Opening an additional shell, also "df" command causes client hang.
I can't manually re-mount the NFS share. It hangs again.
Obviously I have no firewall rules offending NFS transfer (all traffic is allowed on that NIC)
I tried to flag the "Disable Scrubbing" and the other option described as possible resolution of NFS trafic issue in the in Advanced -> Firewall options, but this doesn't work for me.
Does anyone has some suggestion to go on with debugging?

Many thanks!
g