xfce4-terminal does not appear to support "Application mode"
There is (in xterm) a functionality called "application mode" that prevents the terminal from interpreting numpad entries and translating them automatically - instead, the key codes are sent directly to the running application. This allows for making numpad 7 different from "main keyboard 7", etc (usually requires numlock to be off - but in xfce4-terminal, numlock off just generated the same key sequences you would see for home, pgup, etc). I would very much like to see some mechanism implemented that allows for the numpad to generate unique sequences. Attaching a text copy of the help from tinyfugue that describes this functionality in xtermtf_appmode_desc.txt