This is a rare item that seems to be lost from every car. After some encouragement, Ortmanns has decided to reproduce the spare tire cover for the s600. A big thank you for this one. The manufacturer had a technical problem producing it in black, so the item will be produced in white and sprayed black. If you want to capture the luster of the original use a vynil paint that is made for dash boards and door panels. The vynil paint is durable and has the right sheen.
Photos below, the original part, the white reporduction parts from Ortmann, and the location of the cover in the Honda Parts book.