This code from Charly, Felix and others is what we were looking for:
FUNCTION ConectaLDAP()
LOCAL lOk := FALSE
TRY
// Creamos el objeto ADO de conexión
oConexion:= TOleAuto():new( "ADODB.Connection" )
oConexion:Provider:= 'ADsDSOObject'
oProperties := oConexion:Properties( 'User ID' )
oProperties:value := 'Your User'
oProperties := oConexion:Properties( 'Password' )
oProperties:value := 'Your Password'
oProperties := oConexion:Properties( 'Encrypt Password' )
oProperties:value := TRUE
// Abrimos la conexión
oConexion:Open( "Active Directory Provider" )
lOk := TRUE
CATCH oError
AdoError( oError, lMessage )
//xBrowse( oError )
END
RETURN lOk
