Umm..did you look in the Theme pack? There should be a logotemplate.jpg file. You can open it in your Grpahics program liek Fireworks or PhotoShop and then just add your Text to it. It is blank and in the same graphic as the header background.
It should be in the root dir. of the pack.
If you can't find it, holler back and I'll give a link to it.

mikem