If you do this, make sure you keep the two fog light leads (one is supply and one is feed to lights) connected together as your fog lights will mysteriously stop working unless this is connected correctly.
This is a good point. On a proper install the fog light on the car should be disconnected by a little switch in the socket when the trailer lead is plugged in, hence the feed to the fog light is brought out to a similar contact on the multiway plug for the towbar. I've never bothered to connect this because I barely ever drive in fog* and the contacts in the towing sockets can be unreliable.
When I fitted my electrics I removed the multi way conector and connected all the wires with solder joints and plenty of heat shrink sleeving over them. I just connected the 2 fog light cables together. IIRC, they are the only two wires that go to the connector which are the same colour code and if you look carefully in the multiway connector you'll see the contact that connects them together when no towbar electrics are fitted.
Kevin
* - I define fog (bad enough to use a fog light) as being when navigation is difficult due to the inability to read signs by the side of the road. This differs from the opinion held by most Ford Focus drivers or so it seems.
