UPDATE: I figured it out! After days of reading and not understanding Roland's documentation and searching online, I finally figured out how to assign the A-800 Pro's sliders to control the VR-09B's lower manual drawbars via SysEx! In case anyone else is wondering, my SysEx messages are as follows: F0 41 10 62 12 SS 02 01 0_ DT S1 F7 (substitute _ with offsets 3 - B for each respective drawbar). And below is a breakdown of each byte in case anyone is wondering:

F0 - Exclusive status
41 - Roland's manufacturer ID
10 - Roland's default device ID
62 - Model ID
12 - Command ID: DT1; transfer data
SS - Checksum insertion (A-Pro Editor feature; omit entirely if using another program)
02 - Start address pt. 1: Organ lower
01 - Start address pt. 2: Organ lower
0_ - Address offsets: 3, 4, 5, 6, 7, 8, 9, A, B
DT - Data insertion (A-Pro Editor feature; otherwise manually input each data byte from 08 - 00)
S1 - Checksum insertion (A-Pro Editor feature; otherwise manually input each checksum)
F7 - EOX

If you are using A-Pro Editor, set 'Min Value' to 8 and 'Max Value' to 0 to create the "pull down to increase" effect of real drawbars.

This was actually my first MIDI implementation project ever and I'm now excited to see what more I can learn and do with it in the future!
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Hey, all. Hammond B3 enthusiast and total MIDI noob here. So I have a VR-09B V-combo organ and an A-800 Pro MIDI keyboard (with 9 sliders), both Roland products. I also have two MIDI cables. I would like to do a split mode where the A-800 Pro keyboard acts as a lower manual AND its sliders act as lower manual drawbars, while keeping upper manual on the VR-09B itself.
According to Roland support, this should be possible using system exclusive messages. Does anybody have any idea on how this could be achieved? I'll try to share all I know that may help:

• The start address for the organ lower part is 02 01 00, and for the upper part is 02 00 00.
• The 9 drawbar offsets go in ascending order, from 00 03 to 00 0B.
• SOLVED: Each drawbar has a value range of 0 to 8. I'd also like to slide it down to increase the value and up to decrease, much like actual organ drawbars.
• This one might be a bit of a stretch, but if I could get those drumpads on the A-800 Pro to control drum sounds on the VR-09B while also still performing the above, that would be amazing!

Thanks in advance to anyone who's able to help me.