Asp.net developer versed in using the iis rewrite engine,redirects, authorize.net

General information for the business: Estore Website
Description of requirements/functionality: I need an asp.net developer versed in using the iis rewrite engine or versed in coming up with unique solutions. It's a really small problem that someone with expertise can fix. It requires knowledge of redirecting url using the iis rewrite engine, dns systems.

We need to resolve our current url www.jumbocalls.com to www.jumbocalls.com/estore/main.aspx Simple right ? Not exactly. The problem is when we do an iis redirect, our payments no longer go through. When we remove the redirect, payments work fine. We are using authorize.net
Specific technologies required: iis, iis rewrite engine, redirects
Extra notes: So the solution needs to be able to work without breaking other functionlity. What we are seeing now is that any solution we provide, breaks something else, hence, we need someone versed in authorize.net, iis, rewrites, redirects etc