sk4sk4:
I had the exact same problem – every time I saved the code, then looked at it again, it had changed. I’m guessing this is caused by a glitch in the WYSIWYG editor. The easiest way to get around the problem is to to disable the editor temporarily (or permanently, if you want.)
If you don’t know how, it’s very easy. Click the link at top right side labelled ‘my account’. At the bottom of that page, un-tick the box under ‘personal options’ at the bottom of the page. Save changes.
Then go back to your pages area. I would suggest you just delete the page you were working on and create a new one. Now you’ll be able to paste in the HTML you want, and it shouldn’t change at all after you save it. Just be sure to finish all your changes with the file before turning on the WYS editor again.
It worked for me. Good luck!