Curved Shower Rod

I purchased a Moen Inspirations Curved shower rod.
Problem is they say it can't be installed with a fiber glass tub enclosure. Of course they didn't say it on the box just the instructions inside the box.
My shower is a FULL enclosure including a ceiling so there doesn't seem to be any place to mount the side parts which hold the rod. The shower enclosure is a pretty nice one (not a cheap flimsy plastic type). The sides seem pretty sturdy but they extend about 3 or 4 inches away from the wall so there is a large air gap between the fiberglass and the wall. I also don't know for sure if there is drywall or a stud directly behind the part of the enclosure where I need to mount the rod. It can not be mounted outside the enclosure.
Any suggestions? Do you think the fiber glass could take me mounting the rod to it rather than the wall behind it? I was considering using the spring loaded toggle wing anchors.

If you mount it contrary to the instructions you are taking a risk of damaging your shower.

If you do, it is at your own risk.

I would return it and look for something else.

rod

That rod must be anchored into a solid structure in the wall, even when it is not for a plastic shower stall. Your only salvation, if you do decide to mount it to the fiberglass will be if you can find a "ceiling" support to place in the center in order to relieve the torque stress. That will then require that you use a two piece shower curtain closing to the center.

I see no problem putting any shower rod, curved or otherwise, on a fiberglass enclosure. The stess is minimal. Check this link for the Wingits fastening system. Put these in and you could probably do chinups on the rod!

http://estore.websitepros.com/1188279/Detail.bok?no=106