If you have an external MIDI keyboard plugged into an audio interface, then:
1-Create an audio track
2-Make sure the audio track's input is the input to which your MIDI audio out is connected. For example, if you plugged your MIDI keyboard's audio output into input #3 of your XYZ interface, make sure the audio track input at the bottom of the track strip in Inspector says XYZ3 or something similar.
3-Ensure Input echo (the blue thing) is on on both the MIDI and audio tracks.
4-When you are ready to record, arm the audio track and hit record.
When you create the audio track, the input may not default to what need. (In my case, it always defaults to Fantom VS since I use a Roland V-Studio console and interface, and that is never what I want since I set Fantom tracks up by using the Soft Synth insert.) The input for the audio track is small and not obvious so it is easy for this to be set wrong and not noticed, especially since it strips vowels and condenses the input name.
From the other comments above, I may not be answering what you asked but maybe this will help. In my case, getting MIDI keyboards to work in X1 was more confusing than using exotic plug-in virtual instruments. It isn't hard at all, but there are several things that are easy to overlook.
Beagle is right on about the tutorials, by the way. Beagles as a breed are known for their technical expertise.
post edited by konradh - 2011/06/08 10:14:33