asterisk users - Mar 2005 - How to configure directory within voicemail transfer to search by first name?

When I go to Directory() inside extensions.conf, I can set the
dial-context and change the search option to be for first name instead
of last by passing the appropriate options.

How does one configure the directory inside voicemail to do the same
thing (usedirectory=yes inside voicemail.conf). There doesn't seem to
be a way to configure the directory that is presented to the voicemail
user when they want to transfer the call to another person to be
searched by firstname.