[Iluvatar Oakenshield]

first of all: The letter does not have any function in the game for sure, just sell it.

Second: You mentioned that you slept so all the bodies would dissapear, When you do this the wardstone will also dissapear (if it's on the ground) -> Scavengers eat everything!

And finally: Cheating is done this way (at your own risk) You have to edit the file baldur.ini from your BG directory using a text editor like wordpad. Under the [game options] heading add Cheats=1 Now during play press ctrl+tab and a window will pop up, enter the next code: CLUAConsole:CreateItem("MISC2B") and the wardstone will appear in your inventory.

I am not totally sure though if it is the right code, if not there are many fansites of BG who have the complete list of cheat codes

Good luck