alrighty, just tried it.
this is my sound card
I took a guitar cable, plugged one end into the headphone out. the other end plugged into input #2 on the front.
I put a kick drum sample into track 1, set it's monitor to Auto.
I trimmed the start of the kick drum sample so it's a nice clean rising edge waveform.
I set track 2 to OFF and enabled record on it. its input is Ext In and input 2. (the input # Live refers to doesn't have to be the same number printed on your sound card. hit the drop down box to see the meters for the inputs, play the sample and see which meter goes active.)
at the top of the screen I hit record on the transport then hit play.
I had to turn up the volume on the sound card to get a stronger signal.
the recorded signal was delayed by 2ms. so I entered -2 in the delay compensation box.
one thing I forgot, for delay compensation to work the recording track's monitor has to be set to OFF and the delay compensation option has to be ticked in the Options menu.
FWIW to do this quickly you can just hit STOP, tap PLAY twice to reset the transport, then hit RECORD-PLAY-STOP to do the recording. then ctrl-comma to open the preferences. then try again.
I also didn't put my kick drum sample at the very start of time, I set it in 100ms so I can definitely see the start of the recording.
hth it's not as hard as I'm making it out to be. I'm writing quick because I should be playing with some new toys.