I think you had to solder the wire to a 90 deg bend in the bottom of the spring carrier and rather than fitting in holes there were tabs the wire rests on and fold over retainers. There are also guides on the back of the retainers.
I have a 10ft van chassis compare somewhere on rmweb.. edit: http://www.rmweb.co.uk/community/index. ... _p__180631
in fact but unfortunately no shot of the springing. I can try taking one when im back in Manchester after new years though if you're still stuck as its now had the wheels removed and been put in the junk box. The system works though and i've kept my Southern CCTs fitted with the Masokits underframe.