You'll need to take a screenshot of the normal header background, and save a 1px wide slice of it as 'my_head_bg.png' and add it to the project. This way, it'll look just exactly normal.

https://gist.github.com/958426[[posterous-content:scqeJveoHffcEpnEDcww]]

Thanks for reading! And if you want to get in touch, I'd love to hear from you: chris.hulbert at gmail.