Character Sets: default to upper case letters in entry field

Agile comes with pre-loaded character sets, including "All characters with space and Upper Case". This character set allows entry of any alphanumeric character into the field, and automatically converts lower case entries into upper case. That is, if I have a part on a change and I want to modify the revision from A to B, I can enter "b" or "B" into the New Rev field, and the New Rev will display as upper case B.

I am building a character set that excludes certain characters, and I want to duplicate this automatic-upper case function in my own character set. I know how to force the character set to only accept upper case characters, but I don't want my users to get an error message when they enter a lower case character. The character set "All characters with space and Upper Case" does not have the field "Valid Characters Set" populated, so I can't copy the information from there.