Hello. When I bought my car it was missing the trim piece between the side marker and fog light. I bought bumper plate caps (928 505 153 21 70B) and the protective bars (928 505 155 21 70B). I went put them on but can't find anywhere for the protective bars to screw into. Is there another piece missing in there? I have included a pic of what I have now.

Thanks in advance.

 

there is a slide on nut plate missing,
it slides onto the light housing where the hole is,
then a proper screw holds the trim in place

 

There is two types of trim for that area; Euro and US.
The US models got the black bumperettes while the Euro-ROW cars came with a clear lens piece in that area.
You appear to have a Euro-ROW bumper as the mounting bracket for the bumperette and cover piece is missing so there is no way to mount the parts you bought. You need to order the clear Euro trim piece which screws into the empty hole (with a speed nut) you can see in the side of the fog light housing. Plus it looks better IMO.

This is the part # for the Euro trim piece - 928 631 961 00

Here's a pic showing the two types of trim pieces--

 

Seems like the hole on the clear lens lines up pefectly with the hole on the side of the foglight. I wonder how my car got a euro front bumper. From my understanding, the was originally bought in the North East. VIN#WPOAA2922M5810340. It is a 91 S4.