I've just read a few more posts on your thread and taking particular notice of the first pic posted it seems the problem can be cured with silicone but its a bit hit and miss .
This made me think of stuff i found called "Green Stuff" it's like Plasticine but it sets hard in a few hours . People use it to make toy soldiers and stuff . I wonder if you could make some sort of cover , plug , cap or whatever you want to call it that would prevent water getting in then once its set just glue it in place with superglue ?
Green Stuff is a 2 part epoxy putty of sorts you can get it on ebay for about a fiver .