A long, long time ago - in a galaxy far, far away
At similar place in time, I flew B707s in the RAAF for many years and for part of that time did a lot of simulator training and so spent a fair bit of time in the box developing training exercises. In my spare time in the box I used to explore different aspects of operation and the inverted ILS idea came up one day.
The way I did it was to takeoff and fly up the ILS at the upwind end of the runway and level off at 3,000' and accelerate and then at about 15dme perform half a loop, remaining on the LLZ, and re-intercept the G/S and then fly back down the ILS inverted.
As BizJetJock says the localiser appeared normal but the push/pull to stay on the G/S was reversed. The first couple of approaches were a bit of a challenge but after that were not too difficult. I never required any of my students to try flying one though. The B707 sim didn't know it didn't have inverted fuel and oil systems so it would fly around all day 'inverted'.
An interesting but rather pointless excercise which doubtless would have been more of a handfull if you were inverted and hanging in the straps.
Regards,
BH.