Unfortunately, this seems to be yet another problem, caused by the MOSS content filter. When you submit the page, MOSS will validate it and automatically make changes if the content is not valid. You can verify this by trying to enter the same content with the original SharePoint rich text editor.
We have not been able to find a workaround for this behavior yet. It is possible to escape some tags (script, object, iframe) and fool the MOSS content filter. However, it is not possible to escape individual attributes (e.g. href, src).
All the best,
the Telerik team