From what I see this may be one of the systems that X10 will only subtract not enhance the operation of your unit. From what I could see from the manual it is a three wire low voltage interface, if so the following might solve your meet your needs.
If you must have a remote mount the wall mount unit is a box (Outside type) painted would probably look nice. You can use bondo to make it look even better; add some rubber feet, appropriate wire and you are all set.
It appears that it could be a single wire serial interface with power and ground supplied for the electronics in the wall unit. This is just a guess.