Change keybinding Shift-F12 in byobu using tmux backend

Question

I'm using byobu on my desktop and servers. To operate in nestet session I'm using Shift-F12, bun when I want to use e.g. htop (F-keys) I need to:

1. add to ~/.byobu/keybindings.tmux the following:
   bind-key -n C-S-F12 source $BYOBU_PREFIX/share/byobu/keybindings/f-keys.tmux.disable \; display-message "Byobu F-keys: DISABLED"
unbind C-S-F12

2. edit /usr/share/byobu/keybindings/f-keys.tmux to comment out the line:
   bind-key -n C-S-F12 new-window $BYOBU_PREFIX/lib/byobu/include/mondrian
   because whithout this I can't bind nothing new to key sequence.

3. edit share/byobu/keybindings/f-keys.tmux.disable to change the binding
   bind-key -n S-F12 source $BYOBU_PREFIX/share/byobu/keybindings/f-keys.tmux \; display-message "Byobu F-keys: ENABLED"
   to bind to
   C-S-F12

and it works only once becouse of source $BYOBU_PREFIX/share/byobu/keybindings/f-keys.tmux.disable line in /usr/share/byobu/keybindings/f-keys.tmux.

Do any one know how to permanetly change Shift-F12 sequence to Crtl-Shift-F12 using only ~/.byobu/keybindings.tmux or without editing file outside home dir.