Vostro 1520 w/External NumPad - how do I disable numlock on the keyboard, but not the pad?

I just bought a Vostro 1520 and someone is using an external USB keypad with it (he does a lot of data entry with the numpad).  When he turns on numlock, it enables the numlock on the laptop keyboard - which enables the blue number keys that are secondary tot eh letters on the right side of the keyboard.  So, if he needs to use the keypad, he has to hit numlock before and after using it, because if he leaves it on and starts typing letter keys, specifically k, l, etc on the right, the laptop assumes he is trying to use the numbers, not the letters.

The simple fix is to get him an external keyboard, but there is no room on his desk.  Does anyone know how to fix this via the registry, or even through the laptop BIOS, disabling the secondary blue keys on the laptop keyboard?

Thanks!
Dan