If the server returns the above error it typically means that you have issues with some values of elements of your request. Either you are using an older WSDL version, or you have given wrong values in some of the fields (e.g. auditID). This might also be related to using a mix of authenticaiton formats (MSA and IDP) instead of just using one of them and setting the other to null.
This error is thrown by WCF when it tries to validate the response signature. This happens because the signature uses a mix of SHA1 and SHA256 hash algorithms. There is nothing you can do to make WCF accept this. What you should do is implement a custom encoder (which you probably do anyway if you have read my last post) and in the encoder validate the signature by yourself and then remove it from the SOAP.
EDIT: Dwayne McKnight has commented that there is a way around a custom encoder.