Customs and Shipment of seeds

I just placed an order on marijuana-seeds.nl and I want to pay by cash through the mail and I was wondering what would be the safest way to send the money? Should I just put a birthdaycard in there and stuff my money in? And I think it goes through customs so I can't just put it in the blue mail box I have to go to the USPS store and give them it? Also I think I have to put an address to mail back on the envelope so then do I just make one up or do I use my po box address (I dont want it to be traced back to me) Also do I put my name on the inside saying my real name and my address or what? thanks Also what type of mail should I send them?

Bump need quick reply. Will rep !

They can't do anything if there's no proof of seed buying. I'd think you'd be fine with doing it the normal way.

i used credit card and everything was fine. took about 2 weeks shipping. Just make sure to use their stealth option. or get a prepaid debit card but you have to still register it. I would use your real name as well and address. might not be able to ship to a po box. and if you miss the package then you cant pick it up at the post office because they ask for a id.