How to copy a parameter from simple methods and send to context for a following service

[g.fitini]

Hi,
I’ve a service group, so there is something like: 

<service name="xxxxx" engine="group" transaction-timeout="300">
        <group>
            <invoke name="A" result-to-context="true"/>
            <invoke name="B" result-to-context="true"/>
</service>


A is a service like : 


<service name="A" engine="simple" 
            
location="component://content/script/org/ofbiz/content/data/xxServices.xml" 
invoke="ASimple"
        auth="false" >
        <description>PROVA</description>
        <attribute name="uploadedFile" type="java.nio.ByteBuffer" mode="INOUT" 
optional="true"/>
        <attribute name="uploadedFileOut" type="java.nio.ByteBuffer" mode="OUT" 
optional="false"/>      
    </service>

<simple-method method-name="ASimple" >   
************               <!—Here is where i want to make a  copy of my 
uploadedFile into uploadeFileOut. –>     *****************
             <field-to-result field="parameters.uploadedFile" 
result-name="uploadedFileOut"/> 
    </simple-method>


B is a service like:

<service name="B" engine="simple"
            
location="component://content/script/org/ofbiz/content/data/xxServices.xml" 
invoke="BSimple">
        <attribute name="uploadedFileOut" type="java.nio.ByteBuffer" mode="IN" 
optional="false"/> 
    </service>

Now before that BSimple is invocated, the Service ‘B’ broke out. It says that 
it’s necessary the attribute "uploadedFileOut" for input( IN ). I thought that 
during the esecution of simple method ‘ASimple’, i would copy the uploadedFile 
into an attribute ‘uploadedFileOut’ but it doesn’t.
Any explanation?

Thanks