managing nillable elements

[lio axis <li...@gmail.com>]

Hello world,
 I've already asked for this question. Nobody answered. I supposed
i was not clear. If it's too trivial to be answered, please let me know...
 The point is how i can manage axis to control nillable property on elements 
in complex type?
 For instance, if my wsdd file defines the following complex type :
 
<typeMapping qname="ns:resultat" xmlns:ns=http://xxx/types
languageSpecificType="java:org.my.type"
serializer="org.apache.axis.encoding.ser.BeanSerializerFactory"
deserializer="org.apache.axis.encoding.ser.BeanDeserializerFactory"
encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"/> 

How, i force the wsdl to be :
<complexType name="messageTechnique">
<sequence>
.../...
<element name="code" nillable="true" type="xsd:string" />
.../...
</sequence>
</complexType> 

OR :

<element name="code" type="xsd:string" />

Please help,