I spent hours to figure out the routing to tickle the GSi VB-II lower keyboard with Scaler, or with my M-Audio Keystation MINI 32, and the GSi VB-II upper keyboard with my Alesis Q49
I spent so much time as I am very weak in routings 
, so I hope this micro-tutorial can be useful for other poor routers 
Here is the picture
Scaler is linked to one keyboard and this is mandatory: i.e. you must use this input even if you don’t touch that keyboard 
Scaler feeds a MIDI track that feeds the channel 2 of GSi VB-II
A 2nd MIDI track is linked to the other keyboard and feeds the channel 1 of GSi VB-II
GSi VB-II input must be the second keyboard with Track In as sub-input
Then you drop on the 2nd MIDI an Ableton scale that matches with the Scaler scale, launch Scaler in loop and… 
I drooled over a system that would let me play Hammond solos with one hand over an automatic accompaniment since I was 20, and now I got it at long last
Scaler is such a fun!
