Hello,
I'm learning W3C Schema 1.0 and have encountered a problem. I want to 
make a complex type which requires to contain exactly 1 instance of each 
of a list of elements (a, b, c) and at least once a choice of several 
other elements ( d1 | d2 | d3 ). This in any order.

I have come up with the following which is (unfortunately) invalid XSD 1.0:
<complexType name="root">
   <all>
     <element name="a" type="string"></element>
     <element name="b" type="string"></element>
     <element name="c" type="string"></element>
     <choice maxOccurs="unbounded" minOccurs="1">
       <element name="d1" type="string"></element>
       <element name="d2" type="string"></element>
       <element name="d3" type="string"></element>
     </choice>
   </all>
</complexType>

If somebody can help me make up a valid schema for this, I would be very 
thankful. Below are some XML examples to clarify what I expected.

Thanks Phil

=== XML example ===

VALID (a,b,c are there, and at least one d*)
<root>
  <a />
  <b />
  <c />
  <d1 />
</root>

VALID (order changed, that's OK)
<root>
  <a />
  <d1 />
  <c />
  <b />
</root>

VALID (multiple d* are OK)
<root>
  <a />
  <d2 />
  <b />
  <c />
  <d3 />
  <d2 />
</root>

INVALID (a appears twice, bad)
<root>
  <a />
  <b />
  <c />
  <d1 />
  <a />
</root>

INVALID (no d* element, bad)
<root>
  <a />
  <b />
  <c />
</root>