I am using media server but same as below should work for the music server.
First download following link:-
http://www.unixpeople.com/~abarclay/twonkyMusicServer(thanks to abarclay for it originally)
It is pretty self explanitory on how to modify it.
I then put the twonkyvision files in /usr/local/twonky directory and updated the script with the appropriate directories etc.
Finally to get it to load I used the advice of Ray Mitchell using the basic directions from dansguardian.
I copied my updated script into /etc/init.d
I then entered the following commands for it to load upon startup.
/sbin/e-smith/config set twonkyMusicServer service nitscriptorder 55 status enabled
ln -s /etc/rc.d/init.d/e-smith-service /etc/rc.d/rc7.d/S55twonkyMusicServer
Hope this helps.
Laurie