samba-tool classicupgrade not migrating attributes such as givenName, sn, mail

[Justin Foreman]

I'm attempting to migrate a Samba3/LDAP domain to Samba4. The migration
appears to go well, although after it is complete, some critical (for me)
attributes have not carried over from LDAP. Those attributes are givenName,
sn, and mail. They are empty in AD after migration. The users' user ids,
full names, posix attributes, and passwords carry over fine.

Here's the command I'm using to migrate:
/usr/local/samba/bin/samba-tool domain classicupgrade
--dbdir=/root/samba3tdb --use-xattrs=yes --realm=us.x.com /root/smb.conf
--dns-backend=SAMBA_INTERNAL --verbose

Is there some way to tell classicupgrade about how to migrate specific
attributes?

I can provide more details (such as my Samba3 smb.conf and/or
classicupgrade log if desired.) Didn't want to clutter up this initial
message if not necessary. Any help is greatly appreciated.

Here's an example LDAP entry:
# jforeman, People, x.com
dn: uid=jforeman,ou=People,dc=x,dc=com
objectClass: top
objectClass: person
objectClass: organizationalPerson
objectClass: inetOrgPerson
objectClass: posixAccount
objectClass: shadowAccount
objectClass: sambaSamAccount
uid: jforeman
gidNumber: 513
loginShell: /bin/bash
sambaLogonTime: 0
sambaLogoffTime: x
sambaKickoffTime: x
sambaPwdCanChange: 0
sambaSID: x
sambaPrimaryGroupSID: x
displayName: Justin Foreman
gecos: Justin Foreman
cn: Justin Foreman
uidNumber: x
homeDirectory: /share/users/jforeman
sambaPasswordHistory: x
givenName: Justin
sn: Foreman
mail: jforeman at x.com
shadowExpire: x
sambaLMPassword: x
sambaAcctFlags: [U]
sambaPwdMustChange: x
shadowMax: -1
sambaNTPassword: x
sambaPwdLastSet: x

Thanks,
Justin Foreman