Unable create Element with reference.

[anivaros]

Add ability to work with references in element.

Example:

<xs:import schemaLocation="TableViewLayout.xsd" namespace="http://schemas.digdes.com/DDM/ExecutiveWorkplace/2010/TableViewLayout"/>

<!-- LayoutType -->
<xs:element name="Layout" type="LayoutType" />
<xs:complexType name="LayoutType">
	<xs:sequence>
		<xs:element ref="layout:TableViewLayout" minOccurs="0" maxOccurs="1"/>
	</xs:sequence>
	<xs:attribute name="Id" type="ms:guid" use="required"/>
</xs:complexType>

<!-- TableViewLayout root element -->
<xs:element name="TableViewLayout" type="TableViewLayoutType"/>

<!-- TableViewLayoutType -->
<xs:complexType name="TableViewLayoutType">
	<xs:sequence>
		<xs:element name="Column" type="TableColumnType" minOccurs="0" maxOccurs="unbounded"/>
	</xs:sequence>
	<xs:attribute name="Version" type="xs:int" use="optional"/>
</xs:complexType>