Removal of external trim/apply vinyl

Howdy,
 
Well I've had very little luck finding a replacement trim for my 2 door so i've been thinking of some ideas.
What I might do today is head to supercheap and get some sort of putty (maybe you guys can tell me which type), remove the trim like in the photo, jam putty in the holes, sand it back smooth possibly with a dremel, and apply a rally pack decal stripe.
I think it will look a lot tidier than it is at the moment (See photo!). This part of the trim has been missing since I bought the car and it really frustrates me seeing it like that!