Type definition for empty element

What is the correct way to define a type for an empty element just
carrying attributes? 
In particular, one that can later be extended to have content. 
Is it 
 
<complexType name="typeA">
   <attribute name="att1" type="string"/>
</complexType>
 
or 
 
<complexType name="typeA">
   <sequence/>
   <attribute name="att1" type="string"/>
</complexType>
 
I getting tangled up with concerns about anyType vs empty complex type. 
>From http://www.w3.org/TR/2004/REC-xmlschema-1-20041028/#d0e9252
<http://www.w3.org/TR/2004/REC-xmlschema-1-20041028/#d0e9252>  we know
that *all* WXS type declarations are ultimately *restrictions* of
anyType. This can be made explicit as follows: 
 
<complexType name="typeA">
   <sequence/>
   <attribute name="att1" type="string"/>
</complexType>
 
could be strictly expressed 
 
<complexType name="typeA">
   <complexContent>
      <restriction base="anyType">
         <sequence/>
         <attribute name="att1" type="string"/>
      </restriction>
   </complexContent>
</complexType>
 
and I think
 
<complexType name="typeB">
</complexType>
 
implicitly just aliases "anyType" to "typeB".  
 
Hence, I'm wondering if my first example is strictly an "anyType with
attributes", rather than an empty type with attributes. 
 
______
Simon.Cox@csiro.au  CSIRO Exploration & Mining
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