debugging methods in C#.net

Question

I want to be able to step through c#.net 2008 code in a project file that is executed as part of the build process. This project file basically gathers all the third party software dlls and and other company dlls into a general bin directory. The project files are in the project properties area on the publish tab and then the application tab. The project file also does performs other activities that I want to step through the code on.
The project file I am referring to is executed in the postbuild command line section of the startup project for the entire .net solution.
I do not know how to step through this code. I was thinking of either:
I was thinking that I could run the lines that are in the postbuild command line in a .net dos prompt. However, I am not certain how I get get the debug options setup. I would want to be able to step through the code like I would user the debugger in the .net framework.
 Do you have any other ideas?