I finally got my van and did install the LowPro Roof rack with a Fiamma F65 Eagle awning. I did not use the 'awning kit' from Flatline, only their roof rack. When finished, the result is very strong and looks good, but it was a genuine PITA to install. The passenger side oem roof rail has to be removed for the full length Fiamma adapter to fit into the oem rail slot. The awning adapter needs to be fully embedded in sealant/adhesive in the slot, so you won't want to have to remove it later, for say, installing rivnuts (as I did), to mount the Lowpro roof rack to the back side of the awning adapter. You will have to mount the Lowpro passenger side rail pieces in reverse for all of this to work. When reversed, the angle of the roof rack and the awning adapter are exactly the same, and you will need a 1/2" spacer (I used seven), to fit between the rack rails and the backside of the awning adapter. I dry mounted the awning adapter, located and drilled the holes through the Lowpro rails, awning adapter & spacers. I then removed the awning adapter & installed 1/4" rivnuts into the awning adapter. Using adhesive, I then mounted the awning adapter into it's final position.
The big problem is that after you have the awning in place, and you install the roof rack, you cannot then move the horizontal rails of the Lowpro roof rack, because you will not be able to access the passenger side horizontal rail screws, as they are not accessible. I did go ahead and mount the reversed feet of the Lowpro rack through the roof, using backers and sealant. All is extremely sturdy, but the future adjustment of the horizontal roof rails would be extremely time consuming and difficult. That won't be a problem for me, as since I have no more room on the roof anyway.
Here are a couple of pictures - sorry for the poor quality and lighting.