Changing preset voice into a user voice in a recorded song

Hi all,
I am facing a problem I hope some of you already solved. The problem is as follows:
First I recorded a song on my PSR-2100 using preset voice (Live Grand Piano).
Then I realized that the volume of the voice is not high enough, although I increased it to 127 (I remember that many of you already encountered this problem of lack of volume of this voice).
Then I built my own user piano voice and saved it.
Now I tried to change the Program number (in Digital Recording Menu - Song Creator - Page 1-16 - Channel # 3 where I recorded the preset voice I want to change) from "0" into my new user voice (a much stronger piano voice) and it didn't let me do it.
Does anybody know why can't I change the preset voice into a user one, after recording a song?

Best regards,
Lahav

Hi Lahav

go to : http://devoted.to/PSR2K

Chico

Dear Chico,
Thanks for the link. I tried getting the information from PSR-tutorial, but they don't mention there changing preset to user voice after recording a song.
A few months ago I recorded a song and used a preset voice (for example on channel 3). Now I want to change the voice only on channel 3 into a user voice that I saved a few days ago.
When I tried changing Program Change from voice "0" into my user voice, it didn't let me do so.

Lahav