Here is the place that did my mirrors in the event you would like to call them. Perhaps if you could make a sketch of the exisiting rubber dimensions they could fix you up?
Louisville Glass Inc
(303) 225-3432
Address: 1303 Empire Rd, Louisville, CO 80027
Or if that doesn't work look online for "glass setting rubber"... places like this
http://www.bing.com/shopping/search?...5d&wf=Commerce
Hope this helps!