Like Nash said, I have also done some investigation. My evaluation is that making a new interface for Combat Minion so it works with RMU is more work than building something more suiting from scratch. The old percentage activities are built into work flow of RMC and RMU has exchanged that for AP. Additionally the AP-system is built into the critical tables so there are differences in how the injuries to characters need to represented. Skills is also a concern since there is much wider spread of skills that affect things through bonus and number of ranks need to be known by the combat tracker to resolve things.
I have done some blueprinting on a new architecture that support both RMU and previous editions, but trying to smash the old interface into the architecture is not easy. If you did not participate in writing the original code there are bound to be the risk of creating new bugs since you don't understand the tradeoffs when the code was written.
