Due to the nature of the SSL layer in HTTPS, negotiating a secure connection happens before the HTTP protocol is initiated. That means that at the time the SSL layer is in play, the “Host” header has not been sent and, therefore, apache cannot determine which NameVirtualHost to use.
If you’re self-signing your certificates, the browser is going to throw a warning anyway. Might as well just make it as generic as possible and then all traffic running on through the HTTPS port will share the same certificate.