WCF endpoint over https = no wsdl response?

We've had a torturous time getting a client connecting to an externally exposed (http) WCF endpoint. The biggest "fix" was enabling rich error reporting which sped up troubleshooting incredibly. To enable the real error to come through to your client consuming your endpoint (this probably isn't a great Production setting, but it's invaluable in Test), add this to your endpoint behavior:

<behavior name="MetadataBehavior">
<serviceMetadata httpGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="True" />
</behavior>

So we get out of our sandbox environment and get closer to production, and the client starts reporting they can't add our almost-production-but-not-quite endpoint as a service reference. We pick at it and we're seeing errors like this:

The document at the url https://sanitized/sanitized.svc was not recognized as a known document type.
The error message from each known type may help you fix the problem:
- Report from 'https://sanitized/sanitized.svc' is 'The document format is not recognized (the content type is 'text/html; charset=UTF-8').'.
- Report from 'DISCO Document' is 'Discovery document at the URL https://sanitized/sanitized.svc?disco could not be found.'.
- The document format is not recognized.

(etc etc)

It turned out if you called https://sanitized/sanitized.svc?wsdl via your browser, you didn't get a wsdl response. You got the regular "You have created a service." front page. That's what the error message from above is actually saying - it was expecting a text wsdl response and it got a nice html Hello World page from your service.

With that clue, our lead dev on this tracked it down quickly - you have to enable https on the endpoint behavior. We had already set the Security from None to Transport at an earlier point when we had the client go over SSL, but it wasn't enough apparently for this service.
I set the endpoint behavior to this:

<behavior name="MetadataBehavior">
<serviceMetadata httpGetEnabled="true" httpsGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="True" />
</behavior>

and things got much better.