Customizing thumbs up / down rating buttons.

I am working with the roSpringBoardScreen and wondering if there is any way to override the thumbs up and down buttons for rating with my own images. The service I am working on has special images for this purpose and the ultimate goal is to mimic the web experience on the roku.

I would love to do with without having to rewrite roSpringBoard with roScreen... that would be a pain.

Maybe its possible to overlay imageCanvas over SpringBoard?