diff --git a/bundles/org.eclipse.wst.standard.schemas/xsd/wsdl-mime.xsd b/bundles/org.eclipse.wst.standard.schemas/xsd/wsdl-mime.xsd
index f57a532..a6dfbeb 100644
--- a/bundles/org.eclipse.wst.standard.schemas/xsd/wsdl-mime.xsd
+++ b/bundles/org.eclipse.wst.standard.schemas/xsd/wsdl-mime.xsd
@@ -37,7 +37,7 @@
 			<extension base="wsdl:tExtensibilityElement">
 				<sequence/>
 				<attribute name="type" type="string" use="optional"/>
-				<attribute name="part" type="NMTOKEN" use="required"/>
+				<attribute name="part" type="NMTOKEN" use="optional"/>
 			</extension>
 		</complexContent>
 	</complexType>