Failure with EWS via WWSAPI (native code)

Failure with EWS via WWSAPI (native code)

I'm trying to make a request against Exchange(*) EWS
using WWSAPI (native code).
Exchange replies with the error:
 "Cannot process the message because the content type 
 'application/soap+xml; charset=utf-8; 
  action="http://schemas.microsoft.com/exchange/services/2006/messages/ResolveNames"'
  was not the expected type 'text/xml; charset=utf-8'."

It seems the SOAP envelope is ill-formed.
If I manually create the envelope (without WWSAPI) EWS gives no error.

Is WWSAPI supported for EWS?
I can provide all the code for testing.

Thanks & regards
josue

On WebServices tracing I see the following events:

--------------------------------------------------
Sending message - bin  (id: 1): 
3C 73 3A 45 6E 76 65 6C 6F 70 65 20 78 6D 6C 6E 73
3A 73 3D 22 68 74 74 70 3A 2F 2F 77 77 77 2E 77 33
2E 6F 72 67 2F 32 30 30 33 2F 30 35 2F 73 6F 61 70
2D 65 6E 76 65 6C 6F 70 65 22 3E 3C 73 3A 48 65 61
64 65 72 3E 3C 52 65 71 75 65 73 74 53 65 72 76 65
72 56 65 72 73 69 6F 6E 20 56 65 72 73 69 6F 6E 3D
22 45 78 63 68 61 6E 67 65 32 30 31 30 5F 53 50 31
22 20 78 6D 6C 6E 73 3D 22 68 74 74 70 3A 2F 2F 73
63 68 65 6D 61 73 2E 6D 69 63 72 6F 73 6F 66 74 2E
63 6F 6D 2F 65 78 63 68 61 6E 67 65 2F 73 65 72 76
69 63 65 73 2F 32 30 30 36 2F 74 79 70 65 73 22 2F
3E 3C 2F 73 3A 48 65 61 64 65 72 3E 3C 73 3A 42 6F
64 79 3E 3C 52 65 73 6F 6C 76 65 4E 61 6D 65 73 20
52 65 74 75 72 6E 46 75 6C 6C 43 6F 6E 74 61 63 74
44 61 74 61 3D 22 74 72 75 65 22 20 43 6F 6E 74 61
63 74 44 61 74 61 53 68 61 70 65 3D 22 49 64 4F 6E
6C 79 22 20 78 6D 6C 6E 73 3D 22 68 74 74 70 3A 2F
2F 73 63 68 65 6D 61 73 2E 6D 69 63 72 6F 73 6F 66
74 2E 63 6F 6D 2F 65 78 63 68 61 6E 67 65 2F 73 65
72 76 69 63 65 73 2F 32 30 30 36 2F 6D 65 73 73 61
67 65 73 22 3E 3C 55 6E 72 65 73 6F 6C 76 65 64 45
6E 74 72 79 3E 43 6C 65 62 65 72 3C 2F 55 6E 72 65
73 6F 6C 76 65 64 45 6E 74 72 79 3E 3C 2F 52 65 73
6F 6C 76 65 4E 61 6D 65 73 3E 3C 2F 73 3A 42 6F 64
79 3E 3C 2F 73 3A 45 6E 76 65 6C 6F 70 65 3E 
--------------------------------------------------
Sending message        (id: 1): 
<s:Envelope xmlns:s="http://www.w3.org/2003/05/soap-envelope">
  <s:Header>
    <RequestServerVersion Version="Exchange2010_SP1" xmlns="http://schemas.microsoft.com/exchange/services/2006/types"/>
  </s:Header>
  <s:Body>
    <ResolveNames ReturnFullContactData="true" ContactDataShape="IdOnly" xmlns="http://schemas.microsoft.com/exchange/services/2006/messages">
      <UnresolvedEntry>Cleber</UnresolvedEntry>
    </ResolveNames>
  </s:Body>
</s:Envelope>
--------------------------------------------------
Error occurred: 0x803D0000 - The input data was not in the expected format or did not have the expected value.
--------------------------------------------------
Error occurred: 0x0 - The format of the HTTP request was not supported by the server.
--------------------------------------------------
Error occurred: 0x0 - The server returned HTTP status code '415 (0x19F)' with text
'Cannot process the message because the content type 'application/soap+xml;
charset=utf-8; action="http://schemas.microsoft.com/exchange/services/2006/messages/ResolveNames"'
was not the expecte
--------------------------------------------------
Error occurred: 0x0 - There was an error communicating with the endpoint at 'https://gpe-exc2k10/EWS/Exchange.asmx'.
--------------------------------------------------
WsCall API failed by 0x803D0000
--------------------------------------------------

(*) Microsoft Exchange 2010 SP3 with Update Rollup 7