Volvo Repair Questions? Ask a Mechanic for Answers ASAP
If you want to add a Reverse Park Camera you are better off going to your local Volvo Dealer who can supply you with a Reverse Park Camera Kit designed to fit your vehicle.
If you try fitting an aftermarket kit you run the serious risk of damage to the vehicles existing electrical / electronic circuits.
If you are going to fit an aftermarket system then you are best off using a standalone system. Do not touch any of the existing vehicle electrical circuits other than getting your power from a battery live via a fuse.
The Genuine Volvo Kit will be slightly more expensive but it is made for your vehicle and compatible with it. It would end up costing you more in the long run if your vehicle is damaged through fitting aftermarket parts!