Grab a piece of solid surface counter material - you can even find some sections used as door thresholds in the tile section of Lowes - cut it into a square bigger than the diameter of the spout (laminate a few pieces together if you need a thicker piece than you have), then carve / shape one end so it will fit the countour of the surround. Drill a hole in the middle, pull the spout, slide the piece over the pipe and against the wall, re-install the spout, then caulk everything well. If you're lucky it won't look like a complete hack - just a partial one.