transpose key signature

Would be great to have a way to transpose that follows Circle-of-5th conventions. By this I mean: Major keys: C,F,Bb,Eb,Ab,Db,Gb(or F#),B,E,A,D,G Minor keys: A-,D-,G-,C-,F-,Bb-,Eb-(rarely D#-),G#-,C#-,F#-,B-,E- Without this: iReal creates (when transposing) such keys as, for example, Ab-...