Information around here is a bit dispersed :-)
Generally speaking property cases are just different between Digic II cameras and Digic III cameras.
See this page
PropertyCase - CHDK Wiki (Under Digic III)
for a (partial) list of properties.
Other properties are being discovered continuously by different coders on different models, and they are not always udated on the Wiki
For a list of uBasic commands in allBest build, see here:
CHDK firmware usage/AllBest - CHDK WikiFor some help in syntax, download the sources: in trunk/script there are several examples of .bas programs.
As per the on-camera editor, I think someone started working on that but then never finished. it.
See also here:
File/script editor