Download this:
http://www.garrysmod.org/downloads/?a=view&id=70734 , read the instructions on http://www.facepunch.com/showthread.php?p=15609771#post15609771
Then go to your DarkRP gamemode folder, open hints.lua and paste this WITH THE EDITS I TELL YOU TO MAKE after the final hint:
elseif (hint == <number after the last hint’s number>) then
PrintMessageAll(HUD_PRINTTALK , “Type this in console, bind <key> +inventoryaddonmenu, so you can use the inventory!”)
Also, the pocket swep can be enabled/disabled in the DarkRP F4 admin menu.