Hi Giovanni,

I play this song on the BK-7m already. Try using one of the 2 patches which have a rotary switch built-in to the initial touch of the sound. Dyno Rotary and Rotary organ both have this, so if you hit above a certain velocity your get fast rotary, and below that velocity you get slow rotary. It is very useable. Rotary Organ first appeared on the EM2000/G1000 keyboards, so it's been a round for over 10 years and is a great patch.

Alternatively you will have to send some system exclusive from your midi controller, if it can.

To change up from slow rotary to fast rotary, using MFX 88 Vibrato-OD-Rotary send this message:
F0 41 10 00 00 4A 12 18 00 02 31 08 00 00 01 2C F7

To change down from fast rotary to slow rotary, using MFX 88 Vibrato-OD-Rotary send this message:
F0 41 10 00 00 4A 12 18 00 02 31 08 00 00 00 2D F7

I think that will work. The A-Pro series can send system exclusive information, but I am not sure which other controllers can.

John