I'm going to post this here in case anyone wants to know how to do it. I figured this out 18 months ago and forgot I'd done it (I never actually use iOS) until someone over on TGP asked about it. So, for posterity:
ToneX iOS MIDI Preset Selection using AUM
ToneX iOS in AUM with MIDI
Configuring AUM:
Start AUM. Tap +. Select AUDIO. This creates a Channel/Track.
The track has 3 circles. From the top - Input, Plugin, Output.
Tap the hamburger icon (MENU - upper right). Tap Settings.
Select your AI as Input Source. Configure settings as necessary.
Close Settings and Menu. Tap the Input circle at the top of the track.
Tap Hardware Input. Select the USB Outs you want to use.
Tap the Output circle to select the USB Outs.
Tap the Plugin Circle. Tap Audio Unit Extension. Select ToneX.
Tap ToneX. Double-tap the ToneX Menu Bar to expand.
Selecting Presets for MIDI assignment:
In ToneX, Select a Preset. Tap the FOLDER icon. Tap FACTORY. Tap +.
Type in the Preset name (whatever you like, needn't match the ToneX name).
Tap SAVE IN AUM. This saves the selected ToneX preset in a folder in AUM.
You can repeat the last couple of steps to select as many presets as you like before proceeding to the MIDI assignments.
Assigning PC#s to Presets:
Tap the slider looking icon in the ToneX Menu Bar (MIDI Controls).
Tap "No MIDI Source Tap to Connect" (if it appears). Select your controller.
Tap Preset Load. Tap ADD PRESET. Select a preset from the presets saved to AUM previously.
Tap the Preset. The MIDI Learn dialog appears. Tap LEARN. It blinks.
Tap the FS on your controller that sends your chosen PC# for that Preset.
Note if the proper PC# has been assigned.
Repeat until all of your Presets have been assigned MIDI.
NOTE: On my very old iPad, the display takes forever to update, but the actual preset loads almost instantly.
Enjoy!
