You are calling it the 'auxiliary air device' which is a Bosch designation for a part that is not used on our '91 190E. We have a rotary idle air valve instead, and I can tell you where the hoses go if that is your case too. See the pics on thread:
question @ idle air circuit 190E?
and if this looks like yours, then the hose underneath is the idle air intake hose from the lower rubber half of the airflow sensor housing. This intake is above the throttle plate housing. The outlet of the valve goes to the idle air distributor at the intake ports, and 'y's to the pcv device. See the outlet hose detail in the pic (does not show lower hose). In ours, I replaced ALL the hoses, as they had hardened and no longer sealed tightly at the plastic connectors. I also replaced the rubber housing for the same reason. Total cost at Fastlane less than $50.
If you truly have a different intake arrangement, I don't know if this is of much use.