Howto add new attribute via LDIF file

I need to extend our Active Directory schema via an LDIF file.
Does anybody know the syntax and switches I have to use to add a new attribute to the computer class?
The attribute will be used by an application to store a password hash with the local administrator password of the client.

I would like to have an LDIF file which i can import with the LDIFDE tool from Microsoft.
I've tried to write it on my own but I don't know if it's complete or forgotten some switches they have to be in the file.

Here is my attempt:

Code:

dn: CN=PasswordHash,CN=Schema,CN=Configuration,DC=AD,DC=local changetype: add adminDisplayName: PasswordHash attributeID: 1.2.840.113556.1.4.7000.159.24.10.65 cn: CN=PasswordHash description: Password Hash of Local Administrator account isSingleValued: TRUE lDAPDisplayName: PasswordHash distinguishedName: CN=PasswordHash,CN=Schema,CN=Configuration,DC=AD1,DC=local objectCategory: CN=computer,CN=Schema,CN=Configuration,DC=AD1,DC=local objectClass: computer name: PasswordHash searchFlags: 0