Forced SSL breaks mapping

Enabling "force SSL" on a site breaks Google Mapping. This is reproducible on drupal6.demo.civicrm.org Steps to reproduce:
1. Enable Google Mapping and Geocoding at Administer --> System Settings --> Mapping & Geocoding

2. Create a contact record, or use an existing one. Give the contact a real address, and save, so that Google Geocoding looks up the lat/long for that address.

3. On the contact /View page, there should now be a "Map" with thumbpin link next to the contacts address- click that to verify that the address has been geocoded successfully. The google map should show the location of the address of the contact.

4. Now enable "Force SSL" in admin --> Settings --> 'Resource URLs'

5. No return to the contact record, and click on the Map link. The google map image now fails to load.

I though this was because the google mapping scripts were being requested via http , not https . I wrote a small patch (attached) to try to correct this, but it still doesn't display the map image.