Are they running the presentation from Prezi cloud or are they using the desktop version?
[Link: support.prezi.com]The CP3 has a litany of output options:
[Link: ge-el.ru]Why can you not use one of the IR-Serial outputs with an IR Emitter coming out of one of these ports:
Then, on the computer side, use an IR to USB adapter to receive the IR emitted from the CP3 emitter?
[Link: amazon.com]The it's a matter of configuring the commands for mouse-like control (click, etc)