Freenas with 6 NIC

Hi i installed a FreeNAS server with 6 nic card (3 dual port)
and i setted them as LAN, OPT1, OPT2...5 where LAN uses IP
10.10.10.240 and it is connected to a 24 port 10/100 switch.
In development scenario i used the LAN network to access the
NAS from various NFS clients, and all was working fine.
Now to prepare the production environment i wanted to increase
security, the LAN adapter is behind a FW just to access the web
based management interface, while the other 5 OPTx adapters are
connected to the clients via cross cable, the problem is that
i cannot even ping them. so i opened the FreeNAS console and
the various OPTx adapter cannot be pinged by itself.
It seem they are down, while the web interface tells me they are
up correctly (autosense velocity say 1000baseTX, while LAN that
is connected to a stupid switch say 100baseT as expected)

Anyone had some experience with this to give me some advice?

Thanx
Alex