Hi minimivic. If you set the sound card to "Benedini - Mini," the signals from both left and right are combined into the Prop 1 output, so as far as the Beier is concerned, you have a "model with 1 drive motor." As for Prop 2 and 3, they may or may not be of much use. Prop 3 serves as a 16-position RC switch with each position controlling an output as shown on the picture of the Parameter tab on the
Benedini page. The Beier is designed to read a similar type of switch, which they call "Nautic." You would connect Prop 3 from the TCB to "proportional channel #3 (X2/3) or channel #4 (X2/4) of the Beier sound module." However, I am not sure if the positions that we use for the Benedini will be the same positions that the Beier expects, so this may or may not work. You might want to use the Diagnosis function of Beier "Sound-Teacher" program to monitor the outputs of this channel, and see if they can be used.
If not, it might better to set the sound card to "Open Panzer Sound Card" in OP Config. You will not be using the OP Sound Card of course, but this frees up RC Output 6-8 on the TCB (Prop 3 - 1) for other uses. On the Functions tab of OP Config, you can then assign the "Throttle Command" trigger to the "RC Output 8 - Pass-through" function, and then connect Prop 1 to the Beier proportional channel 1 for movement sound.
For other sounds, you can use a pass-through RC channel connected to the Beier. You might also be able to use the General Purpose Outputs A & B on the TCB (set them to Default High) connected to some of the "switching inputs" on the Beier.
You will have to do a lot of experimenting and in the end you may not be able to take full advantage of all the features of the Beier. I will be curious what results you have, so let us know!