Because I don't care about wasd, esdf, and a lot of other control scheme, If you don't like it either, don't be like me: Don't buy it...
Fun fact: Unreal engine know how to handle the numpad keys, but your game don't even know how to map them in the config...

Hmmm, yeah. It seems either the numpad keys are just regular number keys and replaces the weapon buttons, or it seems they are seen as arrow keys and the 5 button will not work.

But, if you are using the numpad, then are you actually even using the number keys then? They are a bit far from the numpad after all.

I mean, you can configure the numpad, its just not as numpad keys, so I am guessing what you are actually complaining about is how you cannot use the number keys and numpad keys at the same time?

Sorry for the late reply, I was on a business trip...
They register as number keys indeed, but in game the numpad doesn't do anything as far as I could tell.
I would have gladly given up the number keys if it worked and wouldn't complain.
I have a razer naga so the number keys are not out of my reach. On a side note movement worked fine when using the number keys but as you might expect it's not that practical.