it depends on what level of restoration you are looking for.

exact copy of the original texture is impossible and nobody has ever done it.

basically the panels are made out of a polypropylene based plastic. epoxy based glue and paint really don't like bonding to this type of plastic without adhesion promoter.
you can get a so so repair by sanding away the chalky part. them apply a adhesion promoter. them give it a coat of epoxy primer. after this dries then give it the proper coating of a textured paint or apply a coat of spray texture then top coat with the proper dye.