Use a vst plugin. SIR is good, and it's freeware http://www.knufinke.de/sir/sir1.html
You won't be able to apply it for monitoring during recording however, as it has mucho latency. But for applying cab-sim impulses to already recorded tracks, adding reverbs etc it's cool.
Just load the plug like any other effect, and from the plug-in load the impulse wav file. Wet/dry mix, apply eq to the impulse, all there and very straightforward.