my simple server don't see parameters! Help me. Please

Hi,
I'm working a day on this simple problem and don't see the solution
the client call a server function with a parameter
with SoapClient->__getLastRequest() I check the request and this seems ok (contain the parameter)

the server response ignore the parameter
where I do wrong?

Help me. Please
Tanks

Paolo

my files:

a simple soap server

server.php

a WSDL file

My_Class.wsdl

and a simple soap client

client.php