Spring RTS Engine

Im asking if its possible to do something like this , so when you zoom all the way out there is a backround at the back.

I think so. So how could i put that into spring?

I was wondering if there was anyway of incorporating a backround onto the map when you zoom out, like that blue screen past the edge of the map, is there anyway to put a diffrent picture there? So it kind of looks similiar to SupCom