none of the usernames and passwords on the machine can get me into the directory
If I set the ibay to "user access via file sharing or ftp" ==> "Write=admin, Read=everyone", and "Public access via web or anonymous ftp" to "Local network (password required)", and use the 'Reset password' link to set a password for the ibay -- then I can login to the ibay with samba for read-only access.
If you set the "user access..." to "Write=everyone,Read=everyone", then you should get read-write access for all SME user or ibay accounts that have passwords set.
If you create a group, then set "Write=group,Read=group", then any users you add to that group should have read/write access to the ibay. (Note: if any of your users are opening their own home folders using their own usernames/passwords, this is the method you will have to use. Users are not able to connect to the SME server using two different usernames at the same time)
Also, samba access seems to be to the root of the ibay, one level above the /files and /html directories.