Go to the I/O page and tap the Tie Lines tab. Choose MixRack Output Sockets and your I/O port on the top row (the port your GigaAce card is in). Then MixRack Input Sockets and Local in the column on the left. Patch the desired channels to the desired outs and your’re good to go. I use this setup for a FOH/MON digital split and it works great, just took me a little while to wrap my head around it.
Hmm. I don’t think gain tracking works across the GigaAce card – that would be incredibly cool though. I think that’s a multiple surface with one mixrack only option. I could be wrong though.