Little ring spread open? Get a #8 torx screwdriver, find a small keyring that wont spread open. Remove the screw that holds the ring, slip in the new ring and hang your key. Your dealer offering 50% is more than most would do. Volvo often asks to see the parts that are being raplaced under warranty. If the dealer cannot produce the part, the ENTIRE claim is denied, not just the cost of the missing part.