Go order one from Gates Rubber. Just measure up what ya got and find a parts store that will custom order for you.
If I had the part number I'd give it to you but I don't anymore. They have all the makings to gen up the part number you need on their web site here. http://www.gates.com/landing/poly/oem.cfm?action=landing&pageID=8&toolboxAdd=14
You'll have to download their catalog but it's not to bad as I recall. Again you will need the dimensions to get what you need.