center awning rafter won't stay on.

our 1998 carrie lite has a 22 foot awning along with the center rafter support. the problem lies with that center rafter. every time I use it I get it secured on the awning tube but as soon as I raise the awning the top of the rafter will fall out of the holder on the camper. I have to use a ladder and hammer the rafter back into the support. any ideas on how I can get it to stay put. the dealer said to squeeze the channel with the rafter in to make it stay and that lasted for a few trips but now it is back to falling out.