I'd say it's next to impossible to record ir transmission from that thing. It just sends many many different shutdown commands. (Impossibe to record with lirc, except to raw code whitch is not supported sending type.)

What I'd do, is to scan through existing known commands and parse power button commands from there. Pack them up and send all of them.

And if someone is interested about day worth of hard work, I'd recommend looking lirc backend code for a sec and writing desktop widget with one button. Progress indicator would also be nice.