LTM and ISA 2006 Web Listener Issue

We are trying to put a LTM in between a Cisco ASA and a MS ISA 2006 server to load balance in our environment. I have been able to successfully achieve this with a simple access rule on the ISA, however I am unable to catch a web listener rule on the ISA when trying that route. I had to turn off the web proxy filter to successfully pass traffic with the access rule. I am unable to do that with a web listener rule. The criteria for both rules to catch are the same. Any help would be appreciated. Thanks.