Change Shift+PageUp and Shift+PageDown keys

Hi, I've been using xfce4-terminal for years now and it's my favorite terminal emulator.

Unfortunately, the new laptop I got doesn't allow me to use the Shift+PageUp and Shift+PageDown keys in xfce4-terminal.

The problem is that my new laptop's keyboard has a silent fan mode toggle with Fn+Shift, which prevents me from pressing Shift+(Fn+Up) for Shift+PageUp.

Therefore, I am looking for a solution on how to change the keyboard shortcuts in xfce4-terminal. Apparently, this key combo is common to all Unix terminal emulators and I have not been able to figure out how I can change it.

Please help, I really like to use xfce4-terminal and this is an important feature for me.