Today I have just done my daughters laguna 2 r/os lock...what a pain it is!!!!. however to release the outer door handle cable you need to do the following.
1 There are two black grommets on the wheel arch side of the door, one small grommet on the edge of the door and one larger on the inner flat side- remove both.
2 In the small hole is a torx head screw. loosen (spray wd40) this and at the same time, push (to remove) the back of the handle cap through the large grommet hole,the small cap part of the handle should be free from the door.
3 Hold main door handle, and carefully slide it towards the rear of the car and towards you (towards the space where the cap was), and lift out (this feels scarry like it will snap).
4 On the outer door face you should now see two holes where there are black lugs, that you need to prise off the door. This then allows the door handle mechanisum to drop down inside the door and give access to the cable.
5 To get the whole lot out of the door put tape over the window to stop it dropping, and remove the two bolts holding the window guide and jiggle the two lock/handle parts out through the door. refitting is reverse of removal, but it took a lot of fiddling around and has to be done by feel as you cannot see inside. it took me about two hours to work out how to do this, you will need another pair of hands when removing the handle mechanisium. BEST OF LUCK