I cannot tell you how to do it but I can tell you what you have to do.
Get a DIF paper tiger. Its a tool that scores wall paper so that water and solution will get behind the paper and neutralize the glue for paper release.
What you have to do is to get behind the paint, and the paper for the water/solution to cause the glue to release and the paper with it. this could be a compounded job as the paint has to be broken up. I do not know if the paper tiger will score the paint.