A Server Page Execution (hiding The Real URL)

I'm looking for a solution for the following problem:

I created ASP code to convert an URL such as:

http://localhost/mypage/category_20/article_15/
into the following URL:

http://localhost/index.asp?page=myp...20&articleid=15

Now, the first URL is submitted by the user. The second one is the real URL,
but not visible for the user. This one should be handled by the web server
internally.

I thought I could accomplish this task with server.execute or
server.transfer, but none of them can handle querystrings. Is there another
way to do this?

Are there perhaps any COM objects? (This will be my last choice, because the
whole system should go running on an iASP (instant ASP) server too if
possible)