Exterior Motion Detector Electrical: How To Splice A Motion Detector Wire From Exterior Plug?

Electrical: How to splice a motion detector wire from exterior plug? - exterior motion detector

I have an external jack is flush with the siding of the house, about two meters above the ground. I want to install a motion sensor in the corner of the house about 4 feet and about 8 feet above the ground.

I lined metal cables and need to know the right way:
1. Splicing of a permanent cable into the socket, hold catches available. I think there should be an extension of the coverage of the movie to shut the wire can delete the background, while the cap on the forehead?
2. Weather 4 "round box on the wall by the light-motion sensors. Is it in the attic of the roof, not that it would be very tight, but it is a good way to do it is not an external cable (which is anchored in the wall it)?

Thank you!