Hello S_Freak,
The rubber sleeve can be pulled off the connector.
Then you need cables with a pin at the end that simply plug into the connector.
Unfortunately, VW is being a pain again. The cables they have in stock are too short, so you'll have to buy half the amount (remember, they have connectors on both ends!), and then cut them in half, because you'll have to solder them anyway on the speaker side (so you'll end up with two cables total).
On the B-pillar side, it's different; small plugs go into the larger ones.
By the way: If you intend to do the same thing with the A-pillar, BE CAREFUL!
VW installed parts that don't have a part number

, so you may need to order all the connectors that don't have a number (for example, I ordered all the 10-pin connectors...).
Have fun!
Jürgen.