Peugeot 406 gear-shift mechanism

I have 406 Estate, 2.0 HDi year modell 2003 and I am missing gear-shift cable. The gear-box type is ML5C and this has three cables, of which I need the one, which makes foreward-backword motion. (The another one makes left-right motion and the third one is for locking reverse gear.)

In the original part list there is number only for the whole gear-shift mechanism and for this one it is 2400Y2, which so includes all above mentioned parts. New mechanisms are not very easily found and the rear ones are expensive. Concerning separate cables the problem is how to find a new cable without any part number. There are separate cables available in net-stores, but it is diffucult to identify the right one. The information of some cables gives gear-box type, other the length of the cable. I have not found any telling the same gear-box code, that I have. The length is uncertain, because I don't know how it is measured. Is it measured from tip to tip or from the centerpoin of the "coupling cup".
I am gratefull about any information concerning this topic. Or if somebody have the mechanism to be sold, I am interested.