KORG Pa4x how to start style with selected STS sound?

after creating a song book entry lets just say MY WAY and I assign Piano to STS #2 as my starting sound......
then save it to songbook,....when I go back to that song in the songbook the keyboard reverts back to STS #1 Accordion....

how do I save songs with the sound I want to begin with STS#2 Piano? what step am I missing here?..

thanx