Set the 'Key Signature of Song" to the concert key of the song.

In the Notation window, hit the 'Opt.' button and in the resulting 'Notation Options' window, make sure the 'Transpose Options' are set to 'Alto Sax +9'.

Go to the Chord Window and enter the chords that appear on your Alto sax sheet music.

Set the other requirements such as the style and the number of bars and choruses.

Push Play. You can display either Eb or concert chords while playing back. The actual key will be the proper concert pitch.

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