Web Service Consume Error

Hi everyone;

we are trying to call an external web service from SAP. we create the client proxy and logical port. when we call the web service we get an exception.

SoapFaultCode:5  Receiver (  Keep-Alive and Close may not be set using this property. Parameter name: value )  | SoapFaultSubcode: InternalServiceFaulthttp://schemas.microsoft.com/net/2005/12/windowscommunicationfoundation/dispatcher

Sınıf istisnası CX_AI_SYSTEM_FAULT

we could not find any option about keep-alive in logical port definition. does anyone have an idea about this error