I have seen this several times and have had the idea of how to fix it but I was missing some steps. The guys over at Xtravirt have it solved. If you haven’t heard of them, take some time on their site as it has a bunch of useful knowledge. Here’s the link to how to solve it:

http://knowledge.xtravirt.com/hot-tips/virtualcenter-2x/12-virtualcenter-2x/32-virtualcenter-and-iis-conflicts.html