yes it can be painted. you just need to scuff the surface so it has some "tooth" for the paint to stick to. a scotch brite pad should do the trick but in this case having it bead blasted would work better since there are so many compound curves and stuff there. you could also use an acid type wheel cleaner to etch the surface though, Eagle One aluminum wheel cleaner would be your best bet, don't get the all wheel cleaner or clear coat safe stuff as they are not acidic enough.