Duplicate the background for every frame of the animation, then place the background layers under each frmae of the anim. Then merge the animation frames down onto the background layers. then save as .gif
EDIT** You beat me to it, Sadistic >=)
That means the rest of this post is pretty much useles. Yeah, you're about right with the directions.
*takes baby-talk tone* OKay.... If you're using Imageready (which I hope you are.), open the animation, and you should see a number of frames.
Open the sig, and you'll see only one frame. Duplicate the sig using the 'duplicate frames' button, untill you have just as many frames of the bacckground as there are in the animation. Then, take the duplicated frames of the originsl sig (not the animation) and put one below each frame of the anim. then, merge each frame of the original black animation down ontp eah frame of the background.
then, save it as a .gif
No offense to Ace, but it was pretty self explained. But, after all I don't know crap about photo editing and I would probably have been confused if posed with the actual task. =P It's always easy to talk shit when your not the one waste deep in it.