Straightforward external MIDI device hook-up in logic

Ok... I understand real world mixers and cables and all that, but the Logic 8 documentation lacks any simple coherent description of how to connect and use external MIDI instruments. Here's the deal:
1. I have a bunch of real instruments, plugged into a mixer.
2. I have the mixer outputs plugged into input 3-4 of a FA101 firewire audio interface.
3. All my MIDI stuff is fully setup and described in Audio MIDI setup
4. All the MIDI stuff shows up in the Library Browser guy on the right of the arrange window and
I can create MIDI tracks for these instruments.

Now... to get their sound into Logic, I create an Audio track whose inputs are 3-4, turn on record for that track, make the MIDI stuff sing and then record the audio as an audio file to use in the mix? Works but kind of clunky...

Is there a way to create and Audio IN object in the Environment so the externally generated audio just gets mixed in in realtime with all the internally generated stuff?

The manuals are not helpful at all in basic sample configurations, except for purely software instruments. Though I did hook up my Space Echo (real box) in Logic. Again not well described in the manual.