Disclaimer: this is no longer necessary. All is well with the roof again. The page is kept for historical purposes.
The switch near the door should work normally, the only thing currently is that the roof in the front uses power from a plug. If the roof is not working, make sure that the roof gets power (see near the electricity box, there should be a hacky cable going from a screw terminal towards a plug downstairs - via a powerblock). Either it's not plugged in or the power block is switched off. Turn it on and use the switch near the door.