[JobSubmit Easylink] Response error with content type not match

I am developing the SOAP client to use JobSubmit Easylink API by WCF in Visual Studio.
When i requested with the default basicHttpBinding, it returned "Unrecognized message version." error message.
I tried to use customBinding with message version SOAP11 (SOAP1.1) but same error occurred.

But i tried to use customBinding with message version SOAP12 (SOAP1.2), it returned below error.
"The content type text/html; charset=UTF-8 of the response message doesnot match the content type of the binding (application/soap+xml; charset=UTF-8). If using a custom encoder, be sure that the IsContentTypeSupported method is implement properly"

This is a wrong binding-setting's problem? Or, source code's problem ?
What is the JobSubmit Easylink API's SOAP version?

I very appreciate if you can help, thank you!