The secondary method option (=Naresh's answer) is one way to achieve the requirement. It will open the transaction in another SAP GUI session automatically, when the user clicks the work item. Sometimes this is problematic, if the user already has max amount of sessions open.
I would most likely choose the attachment option (=the link you proposed). In the decision text you can have a text "If you want to view the sales order, click the "Display sales order" link. And of course then you need to little bit enhance the solution proposed behind link that you proposed, because there the attachment "name" is just something nonsense starting with Z - you should replace it with "Display order" or something that makes sense, and is user-friendly.
Regards,
Karri
