You can't "step into" the code of Text.EXE from your debug session - it's a separate process and doesn't have a debugger associated with it, and it doesn't share the same "process space" as the thread that started it running.
Having said that, you can do it: but it's not as simple as you might want, and you will probably have to call Debug.Break in Test.EXE to start debugging or you won't see anything.
Start reading:
http://msdn.microsoft.com/en-us/library/a329t4ed%28v=VS.90%29.aspx[
^] and don't blame me if your whole system starts to behave oddly or slows down!