MIDI Clock metronome

Hey guys.

I am a new user of Ardour. I need it because I want to create a metronome for my drummer (with a raspberry).

I use a BOSS RC300 Looper and send a SPP Midi clock to Ardour. Ardour synchronizes with my Looper! The only problem I have is that I cant activate the metronome IF ardour is working with an external clock. If I use the internal clock the metronome works…

I come from Reaper and there it is no problem. Hope you can help me! Thanks