Hi Funabshi,
Do you have a Federal Express account or UPS account where you work? If so, all you need to do is schedule a pick up with either carrier and they will go in and pick up. All you would need to do is talk with the person who is selling the mudguards and let them know FED-x or UPS will be in and have them attach the Fed-X or UPS tracking airbill that you can fax or e-mail to them.
If you do not have an account with either carrier, you can go to Federal Express's website and still schedule a pick up and possibly have them pick up and deliver to you on "Collect" basis. Basically they would pick up and then deliver to you and you pay the charges.
You also may go into a Federal Express office in Poland and maybe prepay the pick up and delivery. You will need the address and zip code where the pick up is at and your full address and zip code for delivery. This might be the best way because everything would be prepaid, they would fill out your bill of lading and give you a tracking number for you to track the shipment on their website. Just remeber International shipments can be expensive.
Good Luck
Make and Model