same problem here. i try with T16(0) and T16(1) and put servo in aux1 servo travel just a little with (1) and do nothing with (0), then repeat.. so servo only run one side and dont rewind. (-1) is not alowed...
The shutter accepts standard RC PPM signals. If you can generate it with an arduino servo library, you can control it. Continuous 1500us pulses (22.5ms refresh time) is the idle mode.(Center of the RC transmitter sticks) and +- 300us sides are shutter/video modes. For the first tests please use your transmitter or servo tester to eliminate setup problems. Then replace with your arduino.