wstools error when using xsd:extension in schema

We have the following type extension defined in schema. When runnning wstools against WSDL its looking for wrong QName and throws NullpointerException.

<xsd:simpleType name="NetExplosiveWeightType">
<xsd:restriction base="xsd:decimal">
<xsd:whiteSpace value="collapse" />
<xsd:totalDigits value="9" />
<xsd:fractionDigits value="2" />
</xsd:restriction>
</xsd:simpleType>

<xsd:element name="NetExplosiveWeight">
<xsd:complexType>
<xsd:simpleContent>
<xsd:extension base="tns:NetExplosiveWeightType">
<xsd:attribute name="uom" use="required">
<xsd:simpleType>
<xsd:restriction base="xsd:string">
<xsd:whiteSpace value="collapse" />

<xsd:minLength value="1" />

<xsd:maxLength value="2" />
</xsd:restriction>
</xsd:simpleType>
</xsd:attribute>
</xsd:extension>
</xsd:simpleContent>
</xsd:complexType>
</xsd:element>

Exception in thread "main" java.lang.NullPointerException
at org.jboss.ws.tools.XSDTypeToJava.getVARList(XSDTypeToJava.java:204)
at org.jboss.ws.tools.XSDTypeToJava.createJavaFile(XSDTypeToJava.java:149)
at org.jboss.ws.tools.XSDTypeToJava.createVARforXSElementDeclaration(XSDTypeToJava.java:599)
at org.jboss.ws.tools.XSDTypeToJava.createVARsForElements(XSDTypeToJava.java:522)
at org.jboss.ws.tools.XSDTypeToJava.createVARsforXSParticle(XSDTypeToJava.java:449)
at org.jboss.ws.tools.XSDTypeToJava.getVARList(XSDTypeToJava.java:248)
at org.jboss.ws.tools.XSDTypeToJava.createJavaFile(XSDTypeToJava.java:149)
at org.jboss.ws.tools.XSDTypeToJava.createJavaFile(XSDTypeToJava.java:113)
at org.jboss.ws.tools.WSDLToJava.generateJavaSource(WSDLToJava.java:759)
at org.jboss.ws.tools.WSDLToJava.generateJavaSource(WSDLToJava.java:752)
at org.jboss.ws.tools.WSDLToJava.generateParameter(WSDLToJava.java:577)
at org.jboss.ws.tools.WSDLToJava.appendParameters(WSDLToJava.java:431)
at org.jboss.ws.tools.WSDLToJava.appendDocParameters(WSDLToJava.java:387)
at org.jboss.ws.tools.WSDLToJava.appendMethods(WSDLToJava.java:291)
at org.jboss.ws.tools.WSDLToJava.createSEIFile(WSDLToJava.java:589)
at org.jboss.ws.tools.WSDLToJava.createSEI(WSDLToJava.java:619)
at org.jboss.ws.tools.WSDLToJava.generateSEI(WSDLToJava.java:187)
at org.jboss.ws.tools.helpers.ToolsHelper.handleWSDLToJavaGeneration(ToolsHelper.java:304)
at org.jboss.ws.tools.WSTools.process(WSTools.java:137)
at org.jboss.ws.tools.WSTools.generate(WSTools.java:69)
at org.jboss.ws.tools.WSTools.generate(WSTools.java:119)
at org.jboss.ws.tools.WSTools.main(WSTools.java:58)