Well, the 5 digit codes listed above.
So,
Turn on the TV and Press Audio.
Then
1) Press Setup
2) Point the remote at the Soyo
3) Enter 00191
When you enter the last digit, the TV should turn off (we hope)
Replace 00191 in the above procedure with
00254 which should give Vol+ when you press the 5th digit (4)
00252 Vol-
00195 mute
00000 Ch-
00001 ch+
If this works, I'll provide a full list of 5 digit number and a way to assign them to buttons.