Hi stamko,
you have two options to get picture and sound of your Mac Mini on your BV 7:
1. For picture: Connect the yellow output of the apple adapter with the yellow Composite input at BV 7,
For sound: Connect the audio output of Mac Mini to the red and white Composite input at BV 7.
2. For picture: Connect a S-Video cable between the apple adapter and the above mentioned scart adapter,
For sound: Connect the audio output of Mac Mini to red and white Composite input of the scart adapter,
Finally put the scart adapter into the scart input of BV 7.
The second option gives you the better picture quality of S-Video.
Hope this helps!
Regards
Räuber