You can visit the airside shops and buy replacements for everything they confiscate at security at vastly inflated prices. Then you can take them on board with you!!!
Joking aside, if you operate freighters, then check in is probably not part of your handling contract. You would have to speak to your handling agent staff locally and see if you could check a bag in and have them bring it to the aircraft for you! I'm sure you're aware that the rules also state that if you do check a bag in, it has to go in the aircraft hold...
Oh and these rules about liquids apply to ALL airport staff and ALL aircrew, not just freighters... For example, I can't buy a can of coke from a landside coke machine and take it airside, but I am allowed to buy a can of coke from an airside coke machine...both machines are stocked by the same man using the same supply of coke from the same lorry. Make sense of that if you can!!!!!
You can also bring "essential" liquids through with you as long as they are in 100ml containers in a resealable clear plastic bag...
There is a lengthy thread on this subject in rumours and news...