1. Add a ammo crate and initialize with: "this addWeaponCargo ["FirstAidKit", 20];"
2. Go into game and drop all your gear (at least the first aid kit).
3. Go to crate, drag a first aid kit to your uniform.
4. Go to debug menu, and execute 'player removeItem "FirstAidKit";'
5. Check your gear, the first aid kit added is still there.
6. Go back to debug menu and execute 'player removeWeapon "FirstAidKit";'
7. Check your gear again, first aid kit is still there.
8. Return once again to debug console and execute 'removeAllItems player';
The item is now removed.