Without have more information on your MOTU sound card/interface I would not be able to tell you how to do this specifically.
However, you would essentially need to send the output of your sound card/interface to the RCA tape inputs on the back of the StudioLive 24.4.2AI.
Another option would be to connect the StudioLive 24.4.2AI to your computer via firewire in order to use the console as your sound card/interface and have the output of your DAW set to the 2Track Left and 2Track Right outputs which would send the output to the digital input of the "2Track In" on the console.