NAST-SPRAS value in forms

Hi,

I would like to know if there is a configuration which drives the population of NAST-SPRAS in standard print programs ? When I debug a program (FORM ENTRY), the value of NAST-SPRAS is already populated, is there a IMG transaction related to this ? Where is this set ? I noticed (like in Billing Forms), that the language is related to the country of the ship to party. Please advise. Thanks.