Imagecache: configure image canvas
I assume you are using imagecache_actions module. I enabled imagecache_canvasactions module too that comes with imagecache_actions module.

Once i enable above mentioned modules, i can able to see offset for X &amp; Y while adding Underlay (Background Effect) . See screenshot below. I set offsets to 50 &amp; 40 see the style in action in second image.