I'm trying not to be thrown off by "show a digital reading". I think what you mean is that you want to record the metronome sound into an audio track. Is this correct? I accomplished this very easily by setting my sound card to record the "What you hear" or "Mixed Output" channel. I then armed an empty audio track for recording, turned on the metronome, and recorded. The only hitch is that the recording is delayed a fraction of a second. This is easily corrected by deleting the gap before the first tick.

Or did you mean something else?