# $adsPath is the path to a user object
my $object = Win32::OLE->GetObject($adsPath) or die "...";

my $schemaObj = Win32::OLE->GetObject($object->{Schema}) or die "...";

my @mandatoryAttributes = $schemaObj->{MandatoryProperties};
my @optionalAttributes  = $schemaObj->{OptionalProperties};