Parts are available at Sennheiser USA's website. I don't know if they ship stuff here so I guess it's best to send it to our local service center.
They don't ship. Problem with the local service center is they don't stock. If Senn USA only shipped parts, you'd save the local bureaucracy work and you'd save yourself time dealing with other people. I got a replacement headband pad during the Thomann group buy and ear pads through Senn USA; my brother in California ordered them and shipped them to here technically for free by putting them in a Jelly Bean tin can and puttign that in a balikbayan box. Took a month to get here but at least I got around dealing with customs.
Best move would be to find another online dealer and contact dinkoy to see if he can order them.