[ic] mv_order_subject won't set in log_transaction IC 5.6.0

[IC]

Hi folks,

In interchange 5.6.0 I have found it impossible to set mv_order_subject in
log_transaction. I found a post on the list (link at bottom) from Mike Heins
that referred to a similar problem with mv_order_number, in order to be able
to set mv_order_subject in log_transaction or on a checkout page using an
<input type hidden> I have had to add this to order.pm

		if($Vend::Session->{mv_order_subject}) {
			$value_save->{mv_order_subject} =
				$::Values->{mv_order_subject} =
					$Vend::Session->{mv_order_subject};
		}

Is this the most appropriate way to fix this? 

Reference link:-

http://www.icdevgroup.org/pipermail/interchange-users/2003-March/032398.html

Andy.