How do I enter the procedure type in an AES export declaration?

For an AES export declaration, the procedure type is at header level, with available codes defined as follows:

• B1 - Export declaration and re-export declaration
• B2 - Special procedure - processing - declaration for outward processing
• B3 - Declaration for customs warehousing of Union goods
• B4 - Declaration for dispatch of goods in the context of trade with special fiscal territories