Elements of List<Object> are not added to a WebService Request of a SOAPClient Action

Issue

I have a SOAPClient action. The request object is created in method createRequest() of the WSRequestAction.java class.

The schema contains a complex type such as the one below:

<s:complexType name="AddObjectData">
        <s:sequence>
          <s:choice minOccurs="0" maxOccurs="unbounded">
            <s:element minOccurs="0" maxOccurs="1" name="BoolVal" type="tns:BoolVal" />
            <s:element minOccurs="0" maxOccurs="1" name="SingleVal" type="tns:SingleVal" />

When the StringVal Object is set as follows:

Parameters.setStringVal(stringVal1);

then a single element <v1:StringVal> appears in request which is OK so far.

But as the request has to be sent with 2 StringVal elements, the request object is created as follows:

Parameters.getLongIntValOrStringValOrCurrencyVal().add(stringVal1);
Parameters.getLongIntValOrStringValOrCurrencyVal().add(stringVal2);

Then no single <v1:StringVal> element appears in request.

Why aren't the object elements of object list longIntValOrStringValOrCurrencyVal not added to request?

Note: longIntValOrStringValOrCurrencyVal was generated by wsdl2java from the given schema.