Unfortunatly the studer 500 can handle just the ember protocol, and mairlist can only handle ember+.
Check out this lead >> mAirlist and Velleman USB kit? << >> Koppel faderstart en/of knopstart van je mengtafel met je computer <<, you can use your GPIO for this.
On the other hand there is some bridge software around to converge ember commands into ember+ commands. But this is only IF you have the ember licence in the studer500 !