LG TinyMCE file paths

I’m building a site on a demo server. I have the following in the LG TinyMCE extension settings for the urls:

relative_urls : false,
remove_script_host : true,
document_base_url : "/",
convert_urls : true,

The problem with this is that the demo server url structure is http://demoservername/subdirectory so when I upload an image through EE I have to add subdirectory/ in front of images/uploads. This means that when I move the site to the client’s server none of these image paths will work. Is there a way to set this up so that I won’t have to change any urls after it goes live? I wouldn’t mind having to change the extensions settings, since that would be one quick fix instead of hundreds of links.