Percussion system question


I have added to my layout a two line percussion (Congas) system and I wanted to add notes to the different lines. But I am just able to place them in-between those two lines. With the up and down keys I can force to put a flat in front of the note, but not move it further below or up.
Do I have to do here something else to get it as I want or did I just hit here a limitation of the current software?

Thanks and regards,

Unfortunately this area is not yet fully implemented, Felix, and this is indeed a limitation of Dorico’s current state.