Need Help! IJ mode in Mach 3

I have had a problem posting from Solidcam to Mach 3. After searching online I have found that it is a common problem and that the IJ mode is set to absolute mode instead of incremental IJ mode.

I have put G91.1 in the G code and it sorts out the problem. Apparently I can change the mode by going to General Config in Mach 3... however I cannot find a general config in Mach 3. There doesn't seem to be anything under the config menu that will do it.

How do I do this in Mach 3 so that I don't have to edit the Gcode everytime?

Thanks