Hi Unbrella, I do the same thing as you and have the same problem. I use 7 for crouch and 4 for strafe left and neither key works. I did try posting a message about it yesterday evening and seems to have vanished. After spending 3 hours mucking about I found a solution to it and as a minimum I hope Tripwire post this somewhere as a work around for other users.
1) There is a Killing Floor game folder in your my documents folder which contains user specific information. The folder in steam only contains the default game settings and it is the stuff in your my documents folder that contains your user specific key bindings and settings and can be found at (for Windows 7)
C:\Users\<username>\Documents\my games\KillingFloor2\KFGame\Config\KfInput.ini
2) The bindings you are looking for are right at the bottom of the file so scroll all the way down to the bottom
3) We need to search for the correct entry we need to edit so press Ctrl+f (find command). In my case I searched for "strafeleft" (all one word) so I could bind number 4 to strafe left. In your case you'll need to search for the command you want to bind the key to. There are all there so you might need to browse down the list for the one you want
4) When you see the line it is on it will have the current default key bind and you need to delete it and replace it with number 4. At the moment it will look something like this:
Bindings=(Name="A",Command="GBA_StrafeLeft",Contr...)
and you need to replace the bit aftter Name= with the new key so it will look exactly like this for you for number 4 just with a different command:
Bindings=(Name="NumPadFour",Command="GBA_StrafeLeft",Contr...)
After that just save the file and you are sorted. Same thing works for number 7 if you want to bind that and the name for it is NumPadSeven (make sure you put the caps in).
