I am also trying to this but it makes no sense as I can't find the correct value either! Would be super helpful if Shopify can add this soon! 

We are in the process of migrating to Shopify for our stores. I like your solution for special orders. Are you currently using this same process for special orders now? Ho did you work around the POS terminal not marking orders as fulfilled? 

Yes, understanding your solution would be very helpful to others.