.Net XSD Generation from IList subclasses

I'm programatically generating an XSD file from some C# classes using XmlReflectionImporter. My goal is to generate a schema representing XML similar to the following:

<MyCriteriaList MinimumMatches="2">
  <Criterion>First Criterion</Criterion>
  <Criterion>Second ...</Criterion>
  ...
</MyCriteriaList>

So, an example XSD representing this would be:

<xs:element name="MyCriteriaList" type="ArrayOfCriterion" />
...
<xs:complexType name="ArrayOfCriterium">
  <xs:sequence>
    <xs:element name="Criterion" type="xs:string" />
  </xs:sequence>
  <xs:attribute name="MinimumMatches" type="xs:integer" />
</xs:complexType>

The class that would represent the array of criterion:

public class Criteria : IList<Criterion>
{
    [XmlAttribute]
    public int MinimumMatches { get; set; }

    // IList implementation...
}

However, this generates the following XSD:

<xs:complexType name="ArrayOfCriterion">
  <xs:sequence>
    <xs:element name="Criterion" type="xs:string" />
  </xs:sequence>
</xs:complexType>

The property MinimumMatches is ignored completely and not added as an attribute to ArrayOfCriterion. It's as if the XmlReflectionImporter is detecting Criteria is an implementation of IList and deciding it's a simple array, completely discarding any properties that have been added over and above the implementation.

Any tips greatly appreciated.

Regards,

Steve.