[chirp_devel] New Driver not registering

I have written a driver for the Radio Shack PRO-649 scanner, but it does not register in the directory. I can force it by manually adding the 'rs649' to the __init__.py file, and then it runs perfectly. But why won't it register itself? It is in the \chirp\drivers folder on my Win7 system. Also, does anyone know how to invoke the 'show_instructions' function in the mainapp? I want to provide some configuration hints. I don't find any driver currently using this call.