I don't think adhesive on ensolite would work on curtain rods, because of the leverage factor. You have a lot of leverage on a small base with a curtain rod; vs. no leverage and a huge base on a light
I am going to go with one of two options when I replace mine:
1) In places with an overhead cabinet or shelf, I am going to mount the rod-holders on the underside of the shelf (many people have added forward and rear overhead cabinets, and then side shelves between the rear overhead cabinet and the closet/kitchen cab). (See Larry and Carrie's or others.) That takes care of just about all of them, but if you don't have cabinets, here is a possible alternative:
2) Weld Mount fasteners (see details below). These are used in boatbuilding often now, to hold wire runs and many other things, because holes through the hull create moisture problems. I believe they would be sturdy enough to hold curtains, but since I haven't used them for this yet, I do encourage you to read the holding power for yourself (they list some impressive number, and a wire run in a boat can be quite heavy and bounce around a LOT).
For these I would make a slit in the Ensolite (it's already got holes for the curtain rod now anyway), clean in there with some acetone on a Q-tip or similar, and then slip the disc through and mount it (with it's own special acrylic adhesive).
Link to Weld Mount fasteners at Jamestown Distributors:
Photo of one of the base styles (there are a few):
You could also epoxy mount some blocks to the shell, but I think the Weld Mount system is much more compact and tidy.
3) Some people have mounted the curtain rods to the aluminum frames on the side window, although I prefer mine to go off to the side more, so I'm not going to use this method myself.
Photo of curtain rod mount on window frame: