Hi, there's a plugin which ships in 7.0.182 called Sales Order Custom Fields with UI. In fact I think it was developed in response to a question a raised a year or 2 ago on the forums.
I've used it previously in 7.0.157 and it works a treat.
But in 7.0.182 there are various errors. Would you be able to rewrite it to suit 7.0.182? It's in VB so would be good to keep in VB.
I can then use the 182 sample plugin to update my customer-specific variations.
cheers
Danny