Roli Seaboard is an MPE midi instrument, and Tyros5 doesn't have that technology at all.
(You should read about MPE midi before trying to do this.)
What you need to do is with the Roli Dashboard program, edit the parameters of your Seaboard to does NOT transmit in MPE, (the MPE format transmits in several midi channels, each note assigns it to a different midi channel) so that it only transmits in a single MIDI channel. (Example midi channel 1, and that channel assign it to Right 1.)
Or if you want to use it in midi MPE, what I would try is to make a midi "song" (without midi data) but with ALL 16 midi channels each assigned to the same instrument (violin for example) and configure your Tyros5 to receive the data midi from the Seaboard to that "song".
That in this case, you would be using the "song" as a special "registration" for the Roli Seaboard.
This is something to experiment with, it may not work at all, but I've done some testing with it.
I'm still working on it.
(Also you may need to cancel the midi transmit of some midi parameters on the Seaboard like pressure
Cutoff etc.)