Hello Ivan,

Thanks for the quick response :).

Besides of copy the default model, is there another way to achieve that?

I inherit a sale.order model, and redefine the state fields. When i load/open the web, this model is already updated with the new state. (what i mean is the default state of sale.order model is not affect by the inherit model -- is it possible?) 

Check out this documentation page on inheritence. There are various ways to inherit an object, depending on how do you want to "use" the field in the other class from the new class, that is provided by OpenERP.

For your purpose, maybe inheritance by prototyping is the most appropriate.