Thanks Master Chief and Richard for the clarification! What annoys me the most, is that the tournament organisators ruled for my opponent.
Few weeks ago I played with my German Fallschirmjaegers at a local BA tournament. In my second game my Panzerwerfer 42 (counts as 7+ Armored Car) was hit in the front by a Panzer IV heavy anti tank gun, which has +6 Pen. When rolling to damage my opponent rolled a 1. My interpretation of the rules is, that a damage roll of 1 always fails to damage, regardless of PEN, but my opponent insisted, that 6+1 was enough to do minor damage to my Panzerwerfer. We asked the tournament organisators for rule clarification and they agreed to the ruling of my opponent. Funnily in my third game I had exactly the same situation: Another Panzer IV hitting my Panzerwerfer with his heavy AT gun (in both situations shot was not in long range). After rolling the damage dice and a one came up, my opponent immediately told me that no damage was caused, because 1 always fails! As I will visit another tournament in November, I would like to know which ruling is correct. Thanks in advance for Your answers.