correct me if I'm wrong.
I think what you're saying it is:
the user to carry the correlative number of the service order.
very useful your comment but not what I want. I explain better not want the user to enter the field value. I need you automatically the correlative number of the service order is generated without the user having to enter it when creating the order, in the same way that is done to create the notice.
If you look at the first image only places the class notice, and the next image appears numeor notice, and still has not been saved and the field is disabled and the gender system number of the notice.