Looks like I am a bit late to discover this thread, but here is some general info regarding this issue:
Orbiter uses a low-level mechanism to access the keyboard (via DirectInput). It directly scans the key codes generated by pressed keys, without any higher-level interpretation. Essentially, the keyboard acts like a game pad with a large number of buttons.
For this reason, it shouldn't matter if Numlock is active or not - the keys on the number pads generate the same low-level signals either way. In fact the Numlock key has its own keycode and can be used just like any other key.
If your Laptop numpad doesn't work in Orbiter, it means that it doesn't generate the required keycodes and instead simply clones the keycodes of the normal number keys. This could either be down to the keyboard driver, or (more nastily) to the hardware, i.e. your numpad is hardwired to generate the same low-level output as the number keys. If it's the driver, you might have hope for an update. As it stands now, your numpad isn't properly implemented.
I am slightly confused that so many people in this thread seem to suggest a Numlock-based solution. Does that mean that on your systems the Numlock status actually is relevant for the behaviour in Orbiter? I am surprised, because that would indicate that on those systems Numlock does intercept the low-level scancodes. This isn't supposed to happen.