Call manufacture and see if you are lucky, and can get "J metal wrap" from him or his source. Hopefully already painted your color.
Take off trim and install new J metal and re-install trim. Sounds easy, but will take more time than you'd think. If J wrap is plastic, try Camping world first. They used to or still do have the plastic in shorter lengths.
Camping world number... Catalog Item # 68922 for white.
http://www.campingworld.com/browse/skus/index.cfm?skunum=68922&rewrote&affiliateid=5193&gclid=CNGB5NP04MoCFUiFfgodZH4GowHere is a link for some other parts that get messed up when tires or (gas pumps, sprinklers, etc) get in the way.
http://www.icondirect.com/