i'm doing some synchronization tests with my AD Server and Zimbra. Read about syncing scripts, and the common usage is to extract data from AD via ldapsearch, and insert into zimbra with zmprov.
If possible, i'd like to sync users with ldap command-lines. But the only way i can connect to zimbra ldapserver is anonymous. I tried to make a ldapmodify but i need an user to authenticate:

ldapmodify -x -h -f file.ldif
modifying entry "uid=testuser,ou=people,dc=domain,dc=com"
ldapmodify: Strong(er) authentication required (8)
additional info: modifications require authentication

I tried to authenticate as many ways, '-D uid=admin', '-D uid=admin,ou=people,dc=domain,dc=com', '-D admin@domain' etc...

There's a way to authenticate with the admin user? Or to create an user to connect directly to the ldapserver with write permissions?