Um... The use of Microsoft TMG/ISA for Outlook Web Access publishing is pretty out of date. And that use was usually limited to only that one use; as a proxy for Exchange. Although ISA had web-proxy capability that was VERY rarely utilized. So basically if you have a TMG, 9 times out of 10 that has nothing to do with capturing end-user web traffic.
There are plenty of other products that do do that.
Websense is an industry leader that can be integrated with Cisco networking gear for example.