Inhertiting complex type in XML Schema

[Rizwan Mohammad]

Hi,
Just started reading RMH book for learning web services.
Was going thru some sample to create xml document and xml schema. Struck at the following.
I have xml schema as below.

   
        <element name="address" type="USAddressType"/>
<complexType name="AddressType">
<sequence>
<element name="city" type="string"/>
<element name="state" type="string"/>
<element name="country" type="string"/>
</sequence>
<attribute name="category"/>
</complexType>
<complexType name="USAddressType">
<complexContent>
    <extension base="riz:AddressType">
        <sequence>
           <element name="line1" type="string" minOccurs="0"/>
           <element name="line2" type="string" minOccurs="0"/>
           <element name="zip" type="string"/>
        </sequence>
    </extension>
</complexContent>
</complexType>

with this above schema, i have to define address tag in my xml document
as

  
<address>
        <city>Peoria</city>
<state>Illinois</state>
<country>USA</country>
<line1>line1</line1>
<line2>line2</line2>
<zip>12345</zip>
</address>

I am not able to define address tag elements in the order of line1, line2, city, zip, state, country.
How should I change my xml schema so that I can declare elements in free form. I tried using 'all' instead of sequence but it is not allowing in inheriting of xml schema..
I read from RMH book (Page 48) that "Only single elements may be used in an all group; it can't include other groupings like sequence or all"
Please help me, how can I define my schema to allow flexibility of any order of address tag?
Thanks in advance.

[ August 09, 2006: Message edited by: Rizwan Mohammad ]
[ August 09, 2006: Message edited by: Rizwan Mohammad ]