Object Property- restrictedTo in Profile.daml

As Defined in the Reference Specification for DAML+OIL,

DAML+OIL divides the universe into two disjoint parts. One part consists 
of the values that belong to XML Schema datatypes. This part is called 
the datatype domain. The other part consists of (individual) objects 
that are considered to be members of classes described within DAML+OIL 
(or RDF). This part is called the object domain.

As mentoined in Profile.daml, restrictedTo is an Object Property which 
has as its range any kind of DAML+OIL class (Thing)

<daml:ObjectProperty rdf:ID="restrictedTo">
  <daml:domain rdf:resource="#ParameterDescription" />
  <daml:range rdf:resource="http://www.daml.org/2001/03/daml+oil#Class" />
 </daml:ObjectProperty>

However, in CongoProfile.daml, the restrictyed to parameter for "book" 
has been  defined as

<input>
- <profile:ParameterDescription rdf:ID="BookTitle">
  <profile:parameterName>bookTitle</profile:parameterName>
  <profile:restrictedTo 
rdf:resource="http://www.w3.org/2000/10/XMLSchema.xsd#string" />
  <profile:refersTo 
rdf:resource="http://www.daml.org/services/daml-s/2001/10/Congo.daml#bookName" 
/>
  </profile:ParameterDescription>
  </input>

I am confused by the usage of the range values for restrictedTo 
property. Further the semantic Matchmaker at 
 http://www.damlsmm.ri.cmu.edu/index.html.does not recognise XML Schema 
datatypes as range values for the restrictedTo property.

I would appreciate in any help in this regards

Thanks

Monika
-- 
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Monika Solanki
De Montfort University
Software Technology Research Laboratory
Hawthorn building, H00.18
The Gateway.
Leicester LE1 9BH, UK

phone: +44 (0)116 250 6170 intern: 6170
email: monika@dmu.ac.uk <mailto:monika@dmu.ac.uk>
web: http://www.cse.dmu.ac.uk/~monika/ 
<http://www.cse.dmu.ac.uk/%7Emonika/>
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