XmlObject.xmlText(XmlOptions) outputs xsi:nil="true" where schema definition is minOccurs="0" and default value for nillable="false"

We have defined a type in the schema as...

<xsd:complexType name="MyType">
<xsd:element name="mandatoryElement" type="xsd:string"/>
<xsd:element name="optionalElement" minOccurs="0" type="xsd:string"/>
</xsd:complexType>

According to the XML Schema specification, false is the default value for the optional 'nillable' attribute on xsd:element. So the 'optionalElement' element is nillable='false'.

We instantiate an instance of the MyType class, set the mandatory element and get the value of xmlText()...

MyType type = MyType.Factory.newInstance();
type.setMandatoryElement("someValue");
String xmlText = type.xmlText();

The value of xmlText generated by XMLBeans v2.0 is...

<MyType>
<mandatoryElement>someValue</mandatoryElement>
<optionalElement xsi:nil="true"/>
</MyType>

BUT, we would expect (given that optionalElement is NOT nillable) to see the following...

<MyType>
<mandatoryElement>someValue</mandatoryElement>
</MyType>

Our investigations into the XMLBeans API suggests that it is not possible (via XmlOptions, etc) to suppress the xsi: attributes, so we believe this may be a bug? We are at no point explicitly setting the optionalElement to null.