2007 rear lights upgrade 2012

[RRTdv8Vogue]

Hello,
I bought a 2012 rear lights to upgrade my 2007 model. When I connect it, everything goes well: side, stop, back, except the fog light, that works at the same time that the tail lights. (No flashing) That means that arrives power at the same time to the both tail and fog lights. I need to open the rear light to separate the power. Someone knows how can I open it, without damage?
Thanks

[RRTdv8Vogue]

Hello,
At last my mechanic found the solution.
The problem in my model, december 2007, is that the back lights function with 2 bulbs, that seems the same light, but you can appreciate a thin line that separate the two parts of the light upper and lower. The upper bulb is a normal 5w, but the lower bulb is 21w, and the ECU sends 5w to work like a back light. When I turn on fog switch, ECU send 21w and works like fog light.
The solution is to insert a rele in the fog light, that absorb the 5w signal that send the ECU.

[RRTdv8Vogue]

Here are some images of the work:
In the first you can appreciate the thin line of the two bulbs.
In the second the rele
In the others how it works back and side lights