Glad you're interested in Songsmith. If you've recorded a song already and you're hearing a piano style, click the "browse" button near the word "style" in the lower-left-hand corner of the Songsmith window. This will bring
up the "select style" window.
Many of the default styles don't have a lot of acoustic guitar, but for example, you can choose the "California Soft Rock" style, then click the "mixer" button in the lower-right-hand corner of the Songsmith window, and turn the piano volume
all the way down. The "bluegrass" style is the most acoustic-guitar-heavy of the default styles.
And of course, there are lots more styles you can add if you purchase styles from PG Music:
http://www.pgmusic.com/songsmith.htm
Good luck!
-Dan from the Songsmith Team