Thanks for your comment. I'll create a new patch using constant dictionary.
Before merging this patch, WB_MODE properties should be checked in a propset4 camera (a2200). There is a note in https://trac.assembla.com/chdk/browser/trunk/include/propset4.h:
#define PROPCASE_WB_MODE                         272     // WARNING!!!: This was not verified. 0=AWB, 1=Sunlight, 2=Cloudy, 3=Tungsten, 4=Fluorescent, 5=Fluorescent H, 6=Flash, 7=Underwater, 8=Custom 1, 9=Custom
I don't have access to any propset4 camera to test that.