ComplexType question

Hi,

I'm a little puzzled about the Schema(2) spec (sec 4.3.3) for
ComplexTypes - specifically where the contentType is not specified.
The spec states that this is to be treated as a complexContent
restriction of the ur-type definition and 'details of the mappings
should be modified as necessary'.

My question is : Should I be able to handle a '<restriction ...' (which
doesn't seem to fit the XML syntax definition for ComplexType) - or can
I assume that there is no (further) restriction/extension for this
ComplexType?

On another note, is there a published set of .xsd's which check
conformance to the Schema spec(1&2).

Many Thanks

tim