Do you mean flat or satin? Got a photo?
I don't think you'll be able to get satin by scuffing paint, and I haven't seen flat look good on much. The problem with satin, whether vinyl or paint, is that it wears to glossy. You wind up with glossy spots...Best bet would be vinyl wrap. A thousand bucks and plenty of labor. At least with vinyl, you can pull it off and redo sections (unless it has faded).