To answer my own question, auto-provisioning was turned on but set to periodically for ITSP and Obitalk. Turned them off and now the value set in the OBI200 local config (including the admin password!) stays put. But why doesn't the Obitalk portal doesn't stick though?
Regarding the admin password, where do you set it in the Obitalk portal? Under Expert, all I saw was User, not Admin.
update: LOL, sh*t, it's on the main Obitalk portal page!