Integration

I have a simple problem that I cant find by RTM. One of the parameters in a message to a web service is an array of strings

<wsdl:message name="simpleQueryFetchFilesRequest">
<wsdl:part name="handle" type="xsd:string"/>
<wsdl:part name="tables" type="impl:ArrayOf_xsd_string"/>
<wsdl:part name="qualifier" type="xsd:string"/>
<wsdl:part name="return_url" type="xsd:int"/>
</wsdl:message>

where ArrayOf_xsd_string in the wsdl is defined by

<complexType name="ArrayOf_xsd_string">
<complexContent><restriction base="soapenc:Array"><attribute ref="soapenc:arrayType" wsdl:arrayType="xsd:string[]"/>
</restriction>
</complexContent>
</complexType>

I cant seem to define a valid copy rule in BPEL that initialise the tables parameter.

Can anyone point me in the right direction here?
thanks,
Ross.