Shower curtain is a good choice. I think you should consult some professional services to do this, who has complete knowledge about the process. You can visit http://www.walkinbathtubor.com for more information.
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If there aren't any hidden screws under some kind of channel on your rail, I'd say it must be just some kind of adhesive, and you could just start applying force. Seems fishy though... I'd want to be really sure there aren't screws or rivets somewhere you can't see.