Setting an absolute path on image upload

Hello,
I am using FCK to edit an email newsletter template. Email news need absolute paths to images.

Since the upload config file asks for a path relative to the sites root, the file manager only inserts a relative path (/assets/image/file.jpg)

What I need is the file manager to create links to images that are absolute: http://www.sitename.com/assets/image/file.jpg

Any help?

thanks

Brian