samba - Sep 2011 - Migrating Samba 3.5.6 PDC + OpenLDAP to Samba4

Hi, recently I start to test Samba4, it works great. I want to migrate 
the user data stored in my current LDAP directory. My setup is Samba 
3.5.6 PDC + OpenLDAP. There is any way that i can migrate the current 
accounts and passwords to samba4? any script or utility?

Thanks for your help


German Molano