It's not really a failed request. The server returns the content without compressing it. I have included 2 request trace file contents (these are verbose). Here's the SOAP 1.2 request trace (application/soap+xml) that doesn't get compressed: <?xml version="1.0" encoding="UTF...

For some reason when I register content (MIME) types with the "+" symbol, the IIS7 compression handler does not compress the response. For example, I wrote a WCF service to invoke that exposes SOAP 1.1 and SOAP 1.2 messages. IIS7 correctly compresses the response for text/xml (SOAP 1.1), but...