BG Map Looping

I have a project in the works that uses the map creation tool for SB3. Layer 3 ( the layer i need the help with) has its own propose. its dedicated towards moving clouds in the sky. I Spent all night thinking of how to loop the layer so that when the clouds move off screen (Moving left) the off screen clouds spawn off screen to the right of the player. Causing a loop of unending clouds. All helps appreciated, Thanks :) Edit: I posted on the old site as i cant figure out how to post new threads on Advanced Programming Help on the new one