dennis,
When you upgrade from a previous version all the db users and their permissions are brought over, but the passwords are set to null. Just use the Database Manager to change them to the passwords you want. The caedc user is just the first user alphabetically, so that's what shows in the box when you open it up.
One potential pitfall occurs when you start with a new 4.0 db instead of upgrading. You can add users, but they're all read-only. You can probably log into sybase central as dba and change the permissions, but that can turn into a mess.
Micros added a feature in sp 1 that requires you to enter the old dba password before it can be changed.
There's also an option to reset defaults in the restore database area if you really bang things up and lose all access.
What tables are you looking to write to? Micros has always let the custom user and members of the definition group modify the _def tables but not the _ttl tables.
pat