Debugging In Visual Studio.NET 2005...

Question

I have a component with source. It's been compiled in VS2500. Therefore I also have the DLL. I've installed it into the Toolbox. I create a new c# app and place my component onto the form. The comp's dll path get into the references of my projekt. From the form's code I call one of the comp's methods, and debug it. Everything is ok, but when I want to debug into my comp' source (step into the method), it simply go forward. Why? Once I could achieve to appear an opendialog and it ask for the comp's source file, but unfortunately I can't do this again... Could sy help?