Unfortunately your redirect to
www.yourdomain.com cannot possibly work for https addresses, because if people go to just
https://yourdomain.com they end up connecting to the server and not your website, see the servers SSL Certificate, get a warning, and even if they elect to proceed they end up with a "403 Forbidden" error. This is a crazy setup.
It's not just Comodo which now covers both addresses, even very cheap SSL Certificates cover both - so Geo Trust is the exception to the rule - and when your hosts say that SSL is only valid for a single subdomain they are talking only about the Geo Trust certificate they installed.
Up until 3 years ago we used to buy Geo Trust SSLs for our customers, but switched to Comodo because Geo Trust's Support was so appalling. There is no Geo Trust Support outside of USA office hours or on USA Public Holidays - they forget that their products are sold all around the world.
Vger