Code disappears when moving from visual editor to code view

Hi

I’m building a site for a client which will involve the client posting google maps code and some code for the mBox slideshow when they create new posts.

If I’m using the code view all is fine, but I really want them to be able to switch from one view to the other. The problem I’m having is that WordPress deletes the html for the maps etc. when I go back to visual mode to edit the post further and upload images.

Is there anyway around this? Am I doing something wrong?

Thanks,
Leanda