It is not normal to show different key signatures for different parts of a tune, although it is true that the key centres change throughout a tune. People who are improvising usually pick the key centres from the chord progressions, II, V, I etc, so that they can tell what scale to use. The only software I have seen that picks the appropriate scale (or mode if you must) is the JSSS = Jazz Scale Suggester System. You enter the progression and it picks the scale, or key centre. There is a lite shareware version available.

http://members.w-link.net/~jsss/

Be aware that a key centre might only last for a bar. That is a lot of key changes to make on your music.


Grah Jive Talk
"Don't worry baby, they'll swing their arses off."