How to debug classic ASP pages during AJAX calls in ASP.NET website

Question

I have a legacy classic ASP website with lots of classic AJAX (many ASP files specially made for processing AJAX requests).

We are slowly migrating the website to ASP.NET 2.0 and developing under Visual Web Developer 2005/2008. I notice VWD doesn't debug ASP files. Since we are still migrating a very large website, we are mixing ASP.NET code with classic ASP (ASP.NET pages making AJAX calls to classic ASP pages).

In Visual Studio 2003.NET it supported full server-side debugging in all ASP pages. Now, how can I debug the AJAX classic ASP pages? I tried running Visual Studio 2003.NET and attaching it as a debugger to Internet Explorer, but no breakpoints were stopped at.

Please can someone help. How can we debug classic ASP pages during AJAX calls?