Different key for chords and notes in same layout

Really strange request, I play with a sousaphonist sometimes who prefers written notes in Bb with chord symbols in C. I don’t understand how that works in his brain but that is what he has always done (usually by annotating his parts). Is there an easy way of doing this? Should I just keep the part in C and select all notes and chromatically move them up two half steps?

I believe this menu option from the left panel of Setup mode will give you what you want:

Thanks a lot!