Strange received error in c#

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C#

C#4.0

Hi folks,
If i sending a soap message with soapUI i receive a proper response.
But if i sending the exact same message in c#, I get a proper response in monitoring, but an error in the Visual Studio 10:

Check safety messages failed, with InnerException: Signatures token support not provided.
I'm confused.
The message out and the response in are identical in both case, i'm sure, then the problem is on C# reception, no problem in soap.

Any ideas or suggestions?

Regards.