[Zope] UserCounter and ASP404

I am currently using ASP404 (http://zope.org/Members/hiperlogica/ASP404) to front a Zope server with IIS and UserCounter (http://zope.org/Members/SeanT/UserCounter) on the Zope server. It seems the IP addresses reported in UserCounter are all the IP of the IIS server. Is it possible to modify UserCounter or ASP404 to correct this so that the end user IP is listed ? I am suspecting if it is possible that some change in the ASP404 script is required but exactly what and where is not obvious to me. Has anybody encountered and corrected this problem before?