The WPContainer class defines API properties that get and set the background of the document. [[PS: Is it for the whole document or per page?]]
void setBackgroundColor(Color c) /* [[PS: Where is the Color data type defined? How do I access it?]]*/
Color getBackgroundColor()
void setBorderColor(Color c)
Color getBorderColor()
void setBackgroundImage(String alt)
String getBackgroundImage()
void setBackgroundImageTiled(boolean tiled) /* [[PS: What is getting tiled? Is this if you have multiple images? ]]*/
boolean isBackgroundImageTiled()