Output xml incomplete

Hi

This is my xml output

<?xml version="1.0" encoding="utf-8"?><ns0:Pedidos xmlns:ns0="http://TrabalhoBiz.Envio">

<Cabeçalho>

<Codigo>AMC201206</Codigo>

<Marca>Audi</Marca>

</Cabeçalho><Items>

<Quantidade>3</Quantidade>

<Total></Total>

</Items>

</ns0:Pedidos>

Total field comes empty and i want he put the total amount.

This is my map with my functoid

I want to calculate the Quantidade*PrecoUnitario, and use this to Sum to the Total

Is wrong like this??

thanks