The Boogie Board

Has anyone successfully set this up? Using the 4 cable method and midi out to change channels to use the mark v channels. The GT 8 is changing the the MaG correctly. clean patch one works with the fx. When I step on ch 2 on the GT 8; I see the ch 2 on the mark v turn on but I still hear the clean channel. when I step on 3 and 4 , which should be the heavy tones, they are still sounding like the clean channel. Must be a midi thing but I for the life of me cannot figure it out.

if anyone has used this successfully please help a fellow mesa use out . Just wondering how the GT 8 is set up midi wise.