magento 1.9 soap api xml call to update product custom attribute

Question

I am working on to update product msrp. Below code working for me:

$sku = 'AMC-2.0-10';
$update_data = array (
    'additional_attributes' => array (
        'single_data' => array (
            array ('key' => 'msrp', 'value' => 88)
        )
    )
);
$mage_url = 'http://mystore.com/api/v2_soap?wsdl'; 
$mage_user = 'user'; 
$mage_api_key = 'pass';
$soap = new SoapClient( $mage_url );
$session_id = $soap->login( $mage_user, $mage_api_key );
$update = $soap->catalogProductUpdate($session_id, $sku, $update_data);

but when i try it with postman i get the error that 'Product not exists'

Please check and advise whats wrong in this xml call.

<soapenv:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="urn:Magento">r
   <soapenv:Header/>r
   <soapenv:Body>r
      <urn:catalogProductUpdate soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">r
            <urn:sessionId xsi:type="xsd:string">48daca05f4e6432750199b6295509a24</urn:sessionId>
            <urn:sku xsi:type="xsd:string">AMC-2.0-10</urn:sku>
            <urn:productData>
                <urn:additional_attributes>
                    <urn:single_data>
                        <item>
                            <key>msrp</key>
                            <value>77</value>
                        </item>
                    </urn:single_data>
                </urn:additional_attributes>
            </urn:productData>
        </urn:catalogProductUpdate>
   </soapenv:Body>r
</soapenv:Envelope>

Answer 1

Found the solution to above issue:

this code working fine:

<soapenv:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="urn:Magento">r
   <soapenv:Header/>
 <soapenv:Body>
   <urn:catalogProductUpdate>
     <sessionId xsi:type="xsd:string">48daca05f4e6432750199b6295509a24</sessionId>
     <product xsi:type="xsd:string">AMC-2.0-10</product>
     <urn:productData>
        <urn:additional_attributes>
            <urn:single_data>
                <item>
                    <key>msrp</key>
                    <value>67</value>
                </item>
            </urn:single_data>
        </urn:additional_attributes>
      </urn:productData>
    </urn:catalogProductUpdate>
  </soapenv:Body>
</soapenv:Envelope>