Check "show propcases" and select which 10 propcase values you want to be shown from the "propcase page" parameter.
Default page 0 leads to propcase 0 to 9 being shown as an overlay on the LCD, page 4 is 40 to 49 etc.
I saw you asked about propcases for video modes somewhere else, see the wiki for propcase lists and
http://chdk.wikia.com/wiki/Mode_dial_propcase_values for a570is (digic iii) values for the mode dial propcase.
But note that AFAIK writing to those propcases will not change the video submode.
Also, see the wiki for a script to change and view propcases interactively:
http://chdk.wikia.com/wiki/UBASIC/Scripts:_a_property_case_value_tester
