Get organizationUnit from LDAP with VBA

I'm working with Access 2003 and already have a code that extracts a lot of data from LDAP. Here is what I got:

Set rootDSE = GetObject("LDAP://RootDSE")
domainContainer = rootDSE.Get("defaultNamingContext")

conn.provider = "ADSDSOObject"
conn.Open "ADs Provider"

ldapStr = "<LDAP://" & domainContainer & ">;(& (mailnickname=" & nickname & ") (| (&(objectCategory=person)(objectClass=user)(!(homeMDB=*))(!(msExchHomeServerName=*)))(&(objectCategory=person)(objectClass=user)(|(homeMDB=*)(msExchHomeServerName=*))) ));adspath;subtree"
exchangeRS.Open ldapStr, conn, adOpenStatic, adLockReadOnly
exchangeRS.MoveFirst

Do Until exchangeRS.EOF
    Set oUser = GetObject(exchangeRS.fields(0).value)

    ' The properties below are working
    'oUser.firstName
    'oUser.displayName
    'oUser.title
    'oUser.telephoneNumber
    'oUser.mobile
    'oUser.faxNumber
    'oUser.streetAddress
    'oUser.l
    'oUser.postalCode
    'oUser.mail
Next

I'm able to get a lot of informations for each person in the LDAP database. However, I would also like to get the structural unit. However, oUser.organizationUnit doesn't exit and oUser.OU only contains the top unit, which isn't what I want.

Is there any way to list all properties of oUser to find the right one? Is the ldapStr missing something?

Here is an image of what I want to get (sorry it it's in French):

Is it possible that this is not stored in LDAP? If not, any way to get it from Outlook address book? But I would really prefer getting it from LDAP actually, as every other single information is actually there (which tends me to believe this should be there too).