It does not appear you can do this with the new real-time MIDI input feature. If I try to enter notes into a transposing instrument in Transposed view using written pitch, the notes that appear in the score are as though the keyboard was at concert pitch, although the “audition” notes I hear before and during recording are the transposed pitches.
For example, to clarify: I wish to input a concert G into an A clarinet part (which for them is B flat). I have the score in transposed pitch and Input Pitch set to Written Pitch. While recording I play the B flat on the keyboard, I hear a concert G, but a written D flat (concert B flat) appears in the part. If I set to sounding pitch the audition note and written note are consistent, but then of course I have to play in at concert pitch to get the right notes.
Am I missing something else obvious, or is this a bug, or a limitation of the feature at present? I am copying from a source which is already transposed so it would not make sense to transpose out on the fly in order to have it record at the right pitch (as a horn player I could do this on my own instrument but my keyboard skills are not up to it!).
It also appears as though doubling instruments are treated as grand staff by this feature - I had the odd experience of playing notes into a clarinet in A part and anything above middle C appeared (in a different key again) in the B flat clarinet stave just above (in Galley view, haven’t tried it in layout view). (Though this is avoidable by using the caret of course).