Update: I now recommend using /dev/serial/by-id, which has stable names in it for the all of the Maestro COM ports. See this thread for more info.
Hello.
Using a udev rule, you should be able to assign the virtual serial ports unique names based on the serial number of the Maestro. Please see the discussion in this thread:
Unique Identifier for Simple Motor Controller over ASCII pro
Also, when you get it working, please post your udev rule file here so others can benefit from it.
–David