WSDL "valueofPrompt"

I have a WSDL document generated through SAP Business Objects. And from the PHP language I try to send a constant value to "valueofPrompt" (from the WSDL document). But I do not know well, well how to do it: - (

<s:complexType name="LovValueIndex">
<s:sequence>
  <s:element name="valueofPrompt" type="s:string" /> 
  <s:element name="index" type="s:string" /> 
  </s:sequence>
  </s:complexType>

Please can anyone tell me how to do it?

From PHP I call the WSDL, specifically the GetReportBlock_myReport4 method:

$params = '<GetReportBlock_miInforme4 xmlns="'.$boWSName.'"><login>'.$boUser.'</login><password>'.$boPwd.'</password><refresh>true</refresh></GetReportBlock_miInforme4>';

$result = $client->call('GetReportBlock_miInforme4',$params);

Thanks in advance.

Greetings.