Hi Pete this is nice idea actually I have already seen that it is possible to have a wav file per letter .. you would then have to compose the signal ID (read from the offsets) and send the morse tone to the relative sound card; the problem is how to compose the tone maybe someone expert could indicate how to do it with the Lua plugin.
The speakers are on the sides of the MIP one for each pilot and by acting on the audio control panel (one for Capt and one for F / O) each one can independently select both the microphone with whom to speak and also which channels to listen to (e.g. VHF1, VHF2 , cabin and Morse tones of the radio aids). Basically, the ACP is a mixer and does not interfere with the simulator but only serves to direct and select which sounds (coming from the sim) to send to the speakers; it is also used in output to select which microphone channel to use (eg VHF for communication with air traffic, CABIN, ground ..).
However if you see the video shown in the link it becomes clear ...
Exactly the morse signals are the same for both speakers and each must go to the respective channel of ACP, therefore each channel a sound card; then, depending on what you want to listen to through the ACP, select the relative button (VOR ADF etc. ..) and the signal comes out on the relative speaker. Basically ACP and speaker side Capt and an ACP F / O and speaker but the source is always the same.
..sorry for my english i'm tring make my best for explain😅
V.