No, you can't exclude objects & no it's not possible to apply a shader effect to the background only however...
You could add the background as a scene object & apply a shader object effect to the scene object you've added the background image to.
Check out this thread @ www.visionaire-studio.net/forum/thread/visionaire-shader-toolkit-demo/ for a template of how to apply shader effects to scenes & objects.
For a list of available shader effects check out this page
on the wiki.