I know some have had good luck with using the velcro, I went that way for a while, but found the front door was leaking with the velcro and popup gizmo left on. I ended up removing the velcro from the camper and basically do what Tunce mentioned. I did take it a slight step further, I used pop rivets to attach the clips to the top edge of the gizmos, makes a little easier as the clips are always in place ready to go.
2013 Starcraft Travel Star 229TB
2011 Jayco X17Z(traded in)
2010 Jayco Jay Series 1207(traded for the 17Z)
2011 Chevrolet Silverado 2500HD Z71 CC 6.0L/3.73
Reese "Pro Series" 800lb Trunnion WDH w/sway control