This comes unsourced from Strategy Page, but seems consistent with what I've read else where.
September 3, 2007: The Russian government said that Kosovo is one of Russia's two "red line" issues in Europe. The Russian foreign ministry defined "red line" as an issue where Russian national security or the world order is threatened. Moscow also considers the U.S.-NATO European missile-defense shield to be a "red line" issue. Would Russia really go to war over Kosovo on Serbia's behalf? No, but it would veto a UN resolution, and this rhetoric is designed to have a major political effect. Russia's bellicose language echoes a Serbian statement in late August when the Serbian government said that if Kosovo declares "unilateral independence", Serbia would "inflict some damage in return." The Serbian statement did not indicate what kind of "damage" it would seek to inflict.
This seems to reflect what I've been saying for a while. There is linkage in the Russian foreign policy between the Kosovo issue and the US-NATO missile defense system.
The Russians do not appear to be giving any ground on this issue. They've been resolute, as has been the Serbian government, that they are not willing to flex on the issue of independence in Kosovo.