A roof structure is disclosed for a vehicle that comprises a roof bow including a wall forming part of an exterior roof surface of the vehicle. The wall defines a keyhole opening that is adapted to receive a retainer. A channel is provided on the wall below the keyhole opening that forms a water drain below the keyhole opening with a lower surface of the wall extending over the water drain. A retainer including an anchor portion and an accessory attachment portion extends upwardly from the anchor portion through the slot and is retained in the channel by the flanges.