--- |
    <?xml version="1.0" encoding="UTF-8"?>
    <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" version="1.0">
       <xsd:element name="WIP">
          <xsd:complexType mixed="false">
             <xsd:sequence>
                <xsd:element name="websiteID" type="IntOrParam" minOccurs="1" maxOccurs="1" />
             </xsd:sequence>
          </xsd:complexType>
       </xsd:element>
       <xsd:complexType name="IntOrParam">
          <xsd:sequence minOccurs="1" maxOccurs="1">
             <xsd:element ref="param" minOccurs="1" maxOccurs="1"/>
          </xsd:sequence>
       </xsd:complexType>
       <xsd:element name="param">
          <xsd:complexType mixed="false">
             <xsd:attribute name="name" type="xsd:string" use="required" />
          </xsd:complexType>
       </xsd:element>
       <xsd:element name="text" type="xsd:string" />
    </xsd:schema>

--- |
  <foo />
--- >
FAIL

--- |
  <WIP>
    <websiteID>
      <param name="websiteID" />
    </websiteID>
  </WIP>
--- >
PASS