LDAP Custom Attributes w/ path as value

I'm trying to setup LDAP Custom Attributes and have managed to figure out the easy ones, but the one that is giving me trouble is the manager value. In AD, the value for the 'manager' attribute is a path to the CN containing the name.

For instance: manager: CN=Name\, Last,OU=<>,OU=<>,etc.

I'm using this for manager: attr.Manager First Name =:(|(mail=$sender-email$)(sAMAccountName=$file-owner$)(sAMAccountName=$endpoint-user-name$)):manager