Im sorry.
Im the guy building freedns connector PLUGIN between cwp and freedns.
The idea is to auto-sync custom dns entries from local "named" to the freedns system, commit them.
I think deeply on that, im sure the database is the safest way to store such credentials. Don't?
Even if freedns is not part of, is a perfect pair for CWP on single IP hostings, also a good service even if you can run your own dns.
Regards.
EDITED: I've deciced to put it on database, also editable.