The best you can do is add security to the PDF, but it only works for honest folk.
Thanks for your answer. With different (legal and illegal) programs you can (easily) remove passwords or change the document in a way so that it can be adjusted. I am afraid this is not the solution I am looking for.
Anybody else a different solution?
There is no absolute security for a PDF that has interactive features because flattening removes most of them.
Perhaps you should rasterize the light version in Photoshop and add new hyperlinks to that.