ASP.NET - IIS自定义映射扩展 - 如何？

I am wondering how one goes about creating/rerouting my custom developed .ASPX pages on IIS 6.0 pages to something totally custom w/o the .aspx extension, say, .vato? For example, instead of my page saying: Default.aspx?ID=123, I would like users to see: Default.vato?ID=123. I am wondering how one goes about creating/rero