Using Mainstage 3, EWI, and 2 external instruments

Hello everyone.

After trying many different setups, I think I've finally got my ultimate gig rig ready to go... except for one annoyance that I hope someone can help with. This is probably the wrong forum for this question (it should probably be a mainstage forum somewhere), but this is the only place I can think of that might have someone that really understands this particular use case.

First, the rig:

- Mac Mini (16GB ram, 2x500GB HD, i7 4 core processor) running MainStage 3

- Patchman patches for the ES2 in MainStage

- Bernzilla's Instant EWI for MainStage installed

- Midi Jet wireless midi to connect my EWI to the system

- Turbo VL70-m (configured to accept MIDI on channel 1)

- XV2020 w/patchman soundbanks (also configured to accept midi on channel 1)

- iConnectivity iConnectMIDI4+ for all midi connections

- iConnectivity iConnectAUDIO4+ for audio i/o to the macmini and MainStage

- Samson Airline 77 for wireless mic for my tenor sax (hooked to the iConnectAUDIO4+ for effects in MainStage

All of this is in a nice SKB 4U rack with wheels ... so I don't have to carry it (I'll post some pictures in the Gig Rigs area in the future )

Also, an M-Audio Axiom 49 for other stuff like playing strings in the background or hammering on drum pads.

YAY!

NOW... here's the problem.

One of the things I'd really like to be able to do is layer the sounds with the VL70M and XV2020. I say those two specifically because that's where the problem is with MainStage... layering 2 EXTERNAL instruments. I can layer one of them with software instruments just fine, but as soon as I try to include 2 software instruments in one MainStage patch, only one of them plays... Both of them work fine individually, but if I try to send MIDI events to both at the same time, only one of them gets MIDI.

The way I see it, there's a few possibilities:

1) MainStage only supports one external instrument channel strip in a patch at a time.

2) I've missed some setting in MainStage that I need to allow for multiple external instruments to work properly

3) There's a bug in MainStage

4) I somehow have the iConnectMIDI4+ configured incorrectly

For #1, the wording on this page kind of implies that's the case: https://support.apple.com/kb/PH13578?locale=en_US

My HOPE is that's it's #2 and that someone here knows what I missed.

If anyone has any suggestions, I'll try them tonight when I get home from work (the office frowns upon me bringing my whole setup here and playing with my toys all day )

Thank you everyone for any help you can provide.

- Mike.