Need Some Midi Help Please

[epinvt]

I've recorded a vocal track and want to utilize Waves Harmony Plug In (via midi keyboard) to add harmonies to the recorded vocal track. I'm missing something here, in being able to add midi data to an existing audio track. Hopefully somebody might provide me a "duh!" moment.

[Passionpasi]

Route midi data using "use midi from track" to effect. Open track effect by selecting fx button. There below effect is dropdown list and choose midi track where you use keyboard. Mx10 manual page 532.