ISA 2000

Hi Everybody,

New to ISA - few weeks only?
We are running ISA 2000 on win 2000 box ? configured in integrated mode
Just recently ? few weeks ago-
Some of our users had problem completing orders on an eCommerce web site ? the order gets reset (the items in the shopping cart
Get reset )

After talking to the IT people of the website ? we found out that our
User keeps on bouncing between their ordering servers
And this is due to the source of our user?s IP address changing during a single session

In one single session the connection uses 2 different IPs.
These 2 IPs are:
1- ISA server (outbound IP)
2 ? Our pix ? external interface

Meaning the user connects to the ecommerce web server using our proxy server external ip address Then few moment late the connection bounces back, bypasses the proxy and uses the external interface IP (pix) and that cause the order to get rested

any ideas / help will be appreciated