Bad parameter when specifying lead selector in getMultipleLeads

[Anonymous]

Here is an example for the xml body  i'm sending. If i specify any lead selector i get the error. If i omit it, it works.
I'll appreciate any help. 

<ns1:Body>

    <ns0:paramsGetMultipleLeads>

       <leadSelector xsi:type="ns0:LeadKeySelector">

          <keyType>EMAIL</keyType>

          <keyValues>

             <stringItem>aaa@ccc.com</stringItem>

          </keyValues>

       </leadSelector>

       <batchSize>10</batchSize>

       <includeAttributes>

          <stringItem>MainPhone</stringItem>

       </includeAttributes>

    </ns0:paramsGetMultipleLeads>

 </ns1:Body>

[Anonymous]

I am using version 2.0 of the api.

[Anonymous]

bump

[Anonymous]

Okay, I got a response using the following:
     <LeadKeySelector>
        <keyType>IDNUM</keyType>
        <keyValues>
          <stringItem>574111888</stringItem>
        </keyValues>
      </LeadKeySelector>