I have added a new plugin to the fov_plugins package that allows you to set the brightness/contrast as well as hue/saturation. Additionally it will let you blur the krpano view.
http://fieldofview.github.com/krpano_fovplug…ust/plugin.html
The example linked in that page contains a couple of sliders near the bottom that will let you change the available parameters.
Currently the plugin only applies the adjustments to the image layer. Hotspots and plugins are not affected.