Oh sweet, I just googled broken gopro latch and found a comment on gopros facebook:
GoPro, thank you for the perfect support!
Here the story for all GoPro users who requires support:
The latch of my GoPro housing broke when I closed it (1.5 year old GoPro HD).
I sent a mail at the support, and later a photo of the broken latch.
Now I got a new (free) latch directly sent to my home here in Austria, thank you very much!!! Just in time to take my GoPro with me on the snowy mountains.
But I want to mention, it is recommended to pinch the housing shut with the thumps before closing the latch to prevent such breaks.
So again, thank you very much for the perfect Support!