If you are the same perosn look at the question two below thetford toilet Q:. If not google your caravan maker and if it comes up ask them.
I might be possible I've just been told to cross fix ally strip self tap screw across the roof. Don't take my word for it though and if you do it obvously make sure of solid fixing points.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix caravans/motorhomes.