Using old vintage synth with Tascam US-122 mkII with ubuntu -- synth is not visible in musescore

Hello,
I use a Yamaha SY-22, and I would like to use it as in input keybord in Musescore.
The thing is that this synth is 30+ years old and has only 5DIN Midi connectors and obviously no USB.
In order to connect the synth to USB I use a TASCAM US-122 MKII sound card and mixer.
ALSA sees the TASCAM.
I can send notes from Musescore to my TASCAM sound card so I listen the scores I edit in Musescore.
But I can't do the opposite, use the Synth to write note on a score.
=> Musescore to TASCAM then hear in monitors: This is just USB involved and is OK
=> Synth to TASCAM to Linux to Muscore: NOK. No notes edited.
I setup the Midi by enabling Mido Input to On and in Preferences/Audio and Midi => MIDI input to Midi through (this is the only option I can see). I leave Midi output to "No Device"
Thank you