Anybody familiar with shipping personal items to Serbia?

I had a pallet load of my personal tools shipped over to me a couple of years back and I didn't have to pay any additional taxes.
I seem to recall something about, if they are personal possessions then you sign some declaration for customs (I think you may have to give an approximate value of the items) and customs then issue you some kind of receipt (I never got one). I believe that it has something to do with, if you leave the country then you are expected to take them away with you or, if you no longer have them (perhaps you sold them or they deteriorated through normal wear and tear) you have to provide evidence of their disposal or pay tax on them. Something like that.