Hi MCammuso,
You can find the overall volume (for all 4 Multi Pads simultaneously) in the "Panel" tab of the Mixer ("Panel 1" page). The separate "M. Pad" tab is only for the volume of Audio Link Multi Pads. But beware: These Mixer settings for Audio Link Multi Pads cannot be saved!
By the way, to change the volume of individual (MIDI) Pads of a Multi Pad Bank, you have to go into the Multi Pad Creator and change the value of Controller #7 event (Volume) there.
Best regards,
Chris