asterisk users - Jun 2004 - ast_data, mysql, md5 hashes for passwords

I have asterisk (CVS 7.06.2004) with newest ast_data. My sip-users are
in a MySQL database. Is there a possibility to store the passwords
(column secret) as md5 hashes? In that way that asterisk takes the
password from a client which want to log in, do a md5 hash and compare
that with the one in the database? I don't want them plain text in
the database because of security reasons. At the moment I plan a
web-gui for sip-users to register and making changes on their accounts
themself. It's for my university.
If there is no way with the current source-code, can anybody give me
hints where to do it?

Thanks, Gunnar