as I don't own GigaStudio and I wanted to use GOS with K2, I was looking for MFXs, VST Midi effects or Scripts that could emulate the MaestroTools Legato fonction within K2 and didn't found anything accurate.
Then, I had to learn (a bit..) the Script Language and I wrote this code that seems to do the job pretty well (to me it sounds right, not fully tested though):
if (%CC  > 120)
play_note($EVENT_NOTE + 48,$EVENT_VELOCITY,0,-1)
How it works:
when you use the sustain pedal or input manually CC64 values for legato phrases within your sequencer, the script add the mask samples for any LEG patches from GOS, that's it.
Next goal is to add the AutoAlternator fonction.