Mark,
Many of the settings that you could tweak in SB3 can now be found in the configurations menu in FabMo. Dialog boxes don't work quite the same in FabMo as they did in SB3--but from my talks with the FabMo guys this is something that will be addressed on an app level rather than writing SBP code that prompts questions. Most of the commands still work in SB4 even though they don't bring up dialog windows (MS,.. for example).
If you take a look on the inside of your control box under the power entry you'll notice that there is a thin walled cutout for either usb or ethernet support should that be needed for some features down the road.
Are your desk proto files already calling out MB moves? If you can process the file to swap MX for MB then you could get the tool working using the method that I described. The trick is that the three active axes need to be on channels 1, 2 and 3 for the time being.
We're plugging away at this stuff and I'll keep reminding everyone what the important items are for hardware stuff. Thanks for working with me on this!
Brian