[Asterisk-Users] Asterisk vertical service activation codes

[hugolivude]

Anybody know anything about using "Asterisk vertical service
activation codes" as described in the wiki:

http://www.voip-info.org/tiki-index.php?page=Asterisk+vertical+service+activation+codes

Specifically I'm interested in *0 that (apparently) flashes an
external trunk on bridged channel.  Nothing seems to happen when I use
it though.  Do I need to do something special in extensions.conf or
perhaps features.conf to get this to work?

Thanks,
Hugh