ISA Proxy : Cant Share Internet on 2 diffrent Networks.

Hi,

This is My Senario.

I Have a Proxy Server at my Office. Having 2 NIC
one 10.5.1.0 Other is Connected to DSL Modem via eth.

my first network nic is connected to Switch and swith connects with Cisco 2610 Router and Wireless Ethernet Bridge.

My remote office is then connected with wireless Bridge too. TILL this bridge i have same network address.

But now comes the Other network 10.5.4.0

My remote office can access files and other services. but they cant share the internet via ISA 2004 Until they change their ip to that of 1st network.

where can problem be. I have already defined a rule for 10.5.4.0 for internet access still no effect.
?

Thanks in advance