I don't know for sure but this might be a good place to start. I got the info directly off the Zvezda website.
WORLDWIDE REPRESENTATIVE :
HOBBY PRO MARKETING GmbH (Austria)
• Address: Am Leonhardbach 7, A-8010 Graz, Austria
• Phone: +43 316 323 400
• Fax: +43 316 323 119
• E-mail: office@hobby-pro.com
I hope that helps you out.
Cheers.
GeorgeD.