Providing Client Auth =false in SSL info results in error

[#1]

I'm setting up 2-way ssl from the apigee proxy (on Apigee hosted Edge) to my back-end service, and uploaded the keystore, and truststore. I'm now configuring the proxy to use client authentication - but my back-end service isn't locked down yet, so I'm configuring the proxy so I can enable it once the back-end server is updated.

I added in:

<SSLInfo>
            <Enabled>true</Enabled>  
           <ClientAuthEnabled>true</ClientAuthEnabled>
            <KeyStore>devKeystore</KeyStore>            
	    <KeyAlias>devKey</KeyAlias>            
            <TrustStore>devTrustStore</TrustStore>  
</SSLInfo>

(yes the keystore, alias, and truststore shouldn't be named 'dev...' but bear with me)

When I submit this, I get a wonderfully generic error:

{
  "fault": {
    "faultstring": "The Service is temporarily unavailable",
    "detail": {
      "errorcode": "messaging.adaptors.http.flow.ServiceUnavailable"
    }
  }
}

even changing the ClientAuthEnabled to 'false' gives the same error - if I comment out all besides 'Enabled', it results in successful processing.

My questions:

* shouldn't the error give me something at least a little better to diagnose what's going on?

* what's the point of having a client auth enabled flag if there's no difference between the behavior of true and false

* even if set to true - if the underlying service doesn't ask for it - what's the harm in presenting it?