As most editable GenoPro files are xml based I tried to do some research and stumbled upon these software by Microsoft. (BTW It's free.)

I specially liked:

1. XML notepad
2. XML Diff and patch

... you might see more about them and download them from http://msdn.microsoft.com/XML/XMLDownloads/default.aspx

I hope it will ease your work!

Best of luck!

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"εν οιδα οτι ουδεν οιδα" (Σωκρατησ)  - "The only thing that I know is that I don't know anything" (Socrates)