I found a workaround:
Keys can be rebound by modifying the following script file: \Don't Starve\data\scripts\constants.lua
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Tested in the following environment:
Game: Don't starve (GOG standalone version)
Version: 78281 (hit backspace in-game to see version info in the lower left corner)
Operating System: Windows XP Pro (German)
Keyboard: Standard desktop keyboard with numpad (German layout)
Works with new and saved games
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1. Make a backup-copy (name it constants.lua.BAK, so in case, it's easy to find)
2. Open constants.lua with any text editor (e.g. WordPad, Editor or whatever)
3. Bind the KEY_-constants concerned to new key codes and save the file
Example: Change the entry "KEY_A = 97" to "KEY_A = 260"

3.a) Remapping WASD movement:

Move left: "A" => Numpad 4
Replace the original KEY_A entry with this:
KEY_A = 260 -- Bound to Numpad 4
(In LUA-files, everything after "--" is just a comment (which helps tracking changes in this case))

Move right: "D" => Numpad 6
KEY_D = 262 -- Bound to Numpad 6

Move backward: "S" => Numpad 5
KEY_S = 261 -- Bound to Numpad 5

Move forward: "W" => Numpad 8
KEY_W = 264 -- Bound to Numpad 8

3.b) Remapping camera rotation:

Rotate right: "E" => Numpad 9
KEY_E = 265 -- Bound to Numpad 9

Rotate left: "Q" => Numpad 7
KEY_Q = 263 -- Bound to Numpad 7

3.c) Remapping further usefull keys to numpad:

Show/hide map: "Tab" => "Numpad +"
KEY_TAB = 270 -- Bound to Numpad +

Change spacebar action "Spacebar" => Numpad 0
KEY_SPACE = 256 -- Bound to Numpad 0

Change shift key => Numpad Period
KEY_SHIFT = 266 -- Bound to Numpad Period

Change ctrl key => Numpad Enter
KEY_CTRL = 271 -- Bound to Numpad Enter

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Remarks:
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- Only do this, if you are certain of what you're doing
- Changes in game-files can corrupt your installation of Don't starve
- You might have to reinstall the game, if you do something wrong
- To avoid conflicts, rebind only to keys not serving any purpose in-game, yet
- Any update of Don't Starve could cancel your changes or result in conflicts (so keep a backup of constants.lua)
- Rebinding of the numeric keys 1-0 doesn't work this way
- The original key looses it's function throughout the whole game, you always have to use the "new" key (e.g. when you rebind "A" to "Numpad 4" then Numpad 4 acts as if it were an A and the A key is "dead")
- Numlock must be on, using Windows, otherwise numpad keys act like arrow keys and the binding fails
- If you run the standalone updater (\Don't Starve\updater\16\updater.exe) and use the Check Consistency option, the constants.lua will be replaced by the original and the changes are lost, so keep a backup copy of the modified file

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Reference: Numpad key-codes:
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/ = 267
* = 268
- = 269
+ = 270
Enter = 271
1 = 257
2 = 258
3 = 259
4 = 260
5 = 261
6 = 262
7 = 263
8 = 264
9 = 265
0 = 256
decimal point = 266

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@Zoidberg
I've seen, you're from Belgium, so you probably use an AZERTY-keyboard.
Try this:
KEY_Q = 97 -- In-game Q is now bound to your keyboard A
KEY_A = 113 -- In-game A is now bound to your keyboard Q
KEY_W = 122 -- In-game W is now bound to your keyboard Z

In-game WASD should now correspond to your keyboard ZQSD.
In addition, "A" works for left camera rotation like it should in your layout.