Specific order of fields in Aif messages

Aif-messages require the data to be defined in a specific order. This is why in the schema file, the Aif data-types (declared as complex types) are declared with the xs:sequence indicator:

Example from the DirAddressService:
...

    
      
      
            ...
    
    
    
  

...

This is particularly surprising, as the elements in an entity are always ordered alphabetically... :-\