To meet the paypal requirement of proof of addressee requirement, all I do with express post satchels is fill in the registered post / platinum post lodgement forms (available from any PO) cross out platinum - tick the relevant box, fill out addressee details attach tracking number sticker to form, and get post office to stamp.  No extra $$$ outlay. 

Whenever queried at post offices, other than my regular, I just said I needed for business purposes and they just stamped without further questioning.