Any ideas of how to route a new parking brake cable through the chassis (right side)?

I have had to rebuild the entire rear right suspension in that a new (used) trailing arm, lower wishbone, suspension spring (the one on there was broken!), Bearings, hub, rotor, brake pads, parking brake pads, parking brake cable and complete output shaft (as the CV joint wouldn't move freely) had to be replaced. This was due to discovering that the prior owner had hidden the damage done from an accident that most likely happened in this area as when putting the bolts back in for the upper and lower wishbone to the trailing arm the holes wouldn't match. It was impossible to install the bolts back. Hence why the entire rebuild of this area.

Everything has been done apart from the parking brake cable being reinstalled. It has been installed at the hub end and attached to the parking brake shoes, but when trying to route and snake it back into the chassis so that it can be attached to the handbrake, it is impossible to put back.

The length of threaded rod goes into the hole where the cable originally exited the chassis, but it goes no further and there is approximately 18" of cable left to thread back in.

I have been trying to find any information about how the cable gets to the handbrake, looking for diagrams of where the cable goes (after entering the hole) and what, if any, obstacles there are to getting this done.

I am doing this in a garage and have one side of the car up on a jack stand with the left side wheel on the ground. I also have a 3-ton hydraulic jack that I can use if necessary.

I have found that working under the car gives me limited room and it's very uncomfortable under there.

Am I going to have to remove the exhaust and heat shield to do this job?

Any help would be very greatly appreciated. This car is also the same mechanically (suspension-wise 90%) as the 323i and 325i (manual).

As a side note, I am extremely mad at the engineers who designed this car as all they had to do was put a metal tube in place which allowed the cable to be pushed through all the way to the handbrake so it could be done smoothly. But no! Typical of engineers everywhere (who design absolute crap vehicles nowadays - in terms of making it easy to work on cars) they left this bit out to make it extremely difficult to do a very simple job.