haha, sorry, i was at work when i posted so I couldn't really say what i meant.
The point that I was trying to get across was that you can build that serial device yourself as well. All you need for the whole project to work would be any mechanical type switch you decide to build.
From there, the switches control the serial device, which goes to girder (via the girder serial plugin), which then goes on the control centrafuse hotkeys. Visually, the process looks like this:
mechanical switches -> serial input device -> girder -> centrafuse.
Sounds complicated, but its actually not that bad
If you have any questions, i'd be glad to help out. I think this might be a good route to take if you wanna build custom buttons to interface w/ centrafuse. AFAIK, you only need something that can emulate keystrokes.