That's exactly what I mean. There is no special area for typing in the HTML to edit background images etc. You just have to add it to the profile section where you type all your details in.
The tricky bit is knowing where to add stuff, what ID selectors to use, etc. (I assume you know what I'm talking about). This is solved with the link above -- there's a download at the bottom, that's just a general HTML template. You can then edit that to get what you want, then just paste it onto the profile edit page on myspace as it says in the instructions.