Reverse proxy from Sharepoint site

I have been using ISAPI Rewrite 3.0 http://www.helicontech.com/isapi_rewrite/ for URL rewriting at IIS.
I think this is a great tool. Especially for those who use Apache and its Rewrite module for URL rewrite. The sysntax is the same so you can copy your httpd.conf, the part you do some URL rewrite, over to IIS and it works.

It does proxy too. But unfortunately I found it not work with Sharepoint.
This is because Sharepoint uses "Wildcard application maps". Below is extract from its help.
"This table lists ISAPI applications that are executed before a Web file is processed, regardless of the file name extension. These ISAPI applications are called wildcard script maps. Using wildcard script maps is similar to using ISAPI filters, ..."

I removed it and saw what happens. Bingo. My reverse proxy started working. However, now Sharepoint does not behave as before, so I had to put it back.

The ISAPI_Rewrite.dll works with Sharepoint, because it is an isapi filter, so it gets the requests first.ISAPI_RewriteProxy.dll does not, because it is implemented as an isapi extension, rather than a filter.

Request to .rwhlp URL. The aspnet_isapi.dll, which is registered as the wildcard map, takes and returns 404 because it does not exist…

It is really sad. If the proxy too is implemented as an isapi filter, it should work well also with Sharepoint, which I believe is increasing rapidly its share in the market.