Re: complexType derivation method

Hi,
 
>> b. can I extend a <choice> with another <choice>? and with a
>> <sequence > or with an <all> ?
> 
> You can extend a choice with another choice or a sequence, but not an
> all for the same reasons as given above. Note that when you extend
> with a choice, the two choices are combined in a sequence (the choice
> from the base type followed by the choice from the derived type) and
> not in a choice (all the particles in one big choice).

I was wondering - does anyone knows what it the rationale behind this
constraint? Are there any ways to enable extending a complex type while
allowing inserting elements of the derived type at the beginning of the
content model?
 
Thanks
Ala