Sorry MTI,
I'm might be wrong but I'm not sure I follow you !!!
I mean, I get it that yours are euros.... but

My tailight IS US and it has the foglight socket in. I think in the later years (after 90 or 91) the US w201 had the working back foglight... (someone correct me if i'm wrong)
The foglight is the first bulb closest to the licence plate, no ? that one is wired on mine but no bulb.

So i think they had to have a different connector because it's 6 bulb total inc. fog.
So i'm still in search of that 8pin connector # ???? Anyone knows or am I totally wrong !

thx