Child-Theme Support?

Hi, I think this plugin is exactly what I’m looking for but am having some trouble getting it working. My theme is a child-theme of Twenty-Eleven, and the only sidebars that show up on the Page Editor are the ones in Twenty-Eleven, not the ones in my custom child-theme. Can you offer me any ideas how to get it working with my child-theme?

http://ww.wp.xz.cn/extend/plugins/per-page-sidebar-blocks/