You failed to understand some things. Masking of phone numbers in Outlook is
indeed hard coded and needs to be. Outlook manages the database with which
many PDA apps try to synch. Accordingly, Outlook must present a consistent
database because the synch software must know exactly what format to expect
for each field. That is why there is no option to change those formats. If a
PDA cannot use Outlook's format for some reason, it is up to the synch
software to convert it to some other format. If you think you need a
different format, it is because your PDA synch software is poorly written.
What you found is a reg hack for the operating system that keeps Outlook
from knowing the dialing location so it cannot format the phone number.
You're certainly welcome to use it, and it may work for you, but be advised
that it is an OS hack that doesn't work in all OS and may have unintended
consequences for other apps.