XML Schema Oddities

Hi all XML-gurus!
I am not yet up to full speed on XML schemas so this one may be simple.  When I see the example
below taken from the S2ML v0.8a draft I sense a little problem: It looks like you have
to communicate the following to a partner: We expect to receive an S2ML (http://ns.s2ml.org/s2ml)
"Entitlement" object where "AzData" is a "PaymentRecord" as defined in http://ns.finance-vocab.org/finance.
In addition being awkward, doesn't this also force the receiver to *explicitely* check that the
name-space element in AzData is as agreed upon?

What you would like to communicate is simply a "PaymentRecord" as defined in http://ns.finance-vocab.org/finance.
I.e. S2ML object should optimally be *inherited* and all XML syntax checks be performed automatically.

QUESTION: Is this a built-in limitation of XML schemas?

    <Entitlement>
        <ID>urn:financeDepartment:129de12</ID>
        <Issuer>http://www.example.com/finance/AzEngine</Issuer>
        <Date>2000-10-16T12:34:120-05:00</Date>
        <Audiences>urn:all_example_partners urn:all_local_servers</Audiences>
        <ValidityInterval>
              <NotBefore>2000-10-16T19:34:120-05:00</NotBefore>
              <NotAfter>2000-10-16T20:34:120-05:00</NotAfter>
         </ValidityInterval>
         <DependsOn>urn:authEngine32:xsde12</DependsOn>
         <AzData>
               <SC:PaymentRecord xmlns:SC="http://ns.finance-vocab.org/finance">
                     <SC:TotalDue>19280.76</SC:TotalDue>
                     <SC:Over60Days>1200.00</SC:Over60Days>
                     <SC:Over90Days>10000.00</SC:Over90Days>
               </SC:PaymentRecord>
         </AzData>
         <dsig:Signature>. . . </dsig:Signature>
    </Entitlement>


<Anders>Rundgren</>