url rewriting and authentication

Hello All,



We have an application in which we are planning to have a virtual url
system which is completely driven by configuration files. to accomplish
this we need to receive all urls at the same directory path, and then
according to url rules write them out to different pages which might be
in different folders.



The problem is that some of these folders might be restricted by forms
authentication, so we need to somehow need to fire formsauthentication
after the real url is known, and then redirect to login url with the
virtual url.

The current url rewriting is done by an httpmodule by trapping the
ResolveRequestCache event ( we were using the authorize event, but we
realized that caching was not working with it)



in this scenario is it possible to use the forms authentication module
?, or is there any other valid workaround.

any help or opinion would be appreciated.