Besides the mono and stereo versions, Podium should have detected and created mappings for one multi-input instance (labeled SPAN #1). It appears you have to reconfigure these by hand; make sure the devices of the “shared instance” all have audio inputs and outputs set. You can delete the superfluous MIDI mappings. See picture:
Now you should be able to insert these mappings onto tracks:
If you need another instance of a multi-input SPAN, right-click the folder containing the mappings (in the “devices” panel on the project page or the inspector) and select “New Instance”.
Hope this helps.