Looking for location of Theme files.

I am trying to assemble a movie using the "Reflections (White)" theme. In iDVD I am able to change the font in that theme for the menu components, however in iMovieHD I also want to use the "Opening" and "Title" components from that theme, unfortunately iMovieHD does not provide a way to change the font in those components.

I have read that by using Quartz Composer I can open the individual .qtz files from within the individual themes, however I do not know where these live on the computer. I have looked around within the iMovieHD package as well as iDVD, used Spotlight to search for them but have not found anything that looks even slightly like what I want.

Can any of the hard-core users point me toward the location of the theme files?

Thanks.

-John