Here is the G540 Mach3 XML file for the REV3 G540 boards. This is courtesy of Dan Mauch at Camtronics who was one of our beta testers and was kind enough to provide this to us. If you guys have any questions about it, feel free to ask.
The file is on the "Application Notes" page of our website and is labeled "G540 XML File".
Application Notes
Marcus