You could try to use gconf to set key-bindings...it's what I use.
Then go to Applications > System Tools > Configuration Editor
sudo apt-get install gconf-editor
Expand Apps > Metacity > global_keybindings
From here you need to type in a Value for one of the run_command_#
Expand Apps > Metacity > keybinding_commands
From here you need to type in a Value for the command_# that corresponds with the run_command_#
This will open up the terminal for me when I press Super and T at the same time.