samba - Feb 2015 - How to create one group with the defined Manager

Hello, I want to create a group and define the manager  of it. The attribute is
managedBy, but I don't know how to modify or asign a value to it. I did it
using an ldif file with the following parameters:
dn: CN=MyGroup,CN=Users,DC=dominio,DC=pdc,DC=cu
objectClass: top
objectClass: group
name: MyGroup
managedBy: CN:Yosel,OU=Person,DC=dominio,DC=pdc,DC=cu

but it does not work.