Re: start//empty

> How about
>
> <data type="string">
>   <except>
>     <empty/>
>   </except>
> </data>
>
> Can it be captured by another way?

In exactly the same way as you would exclude any other specific value:

<data type="string">
  <except>
    <value type="string"></value>
  </except>
</data>

James