Yes. I think the only way to do this, though, is using Adobe
Flash. Open the raw Flash file, skin_background_tb.fla, import the
logo file, put it where you want it on the toolbar background, and
export the file as a movie.
You may have to experiment until your logo is far enough to
the right to not be overlapped by the buttons. If I put a logo at
the left, I open each button file in Flash and move it to the
right, then export it. This moves the buttons so that they don't
overlap the logo on the left.
Hope this helps,
Ben