Fitting spring on older Vespa forks???

[eadmr04]

How the hell do you fit the spring on older Vespa forks with the damper and spring. I managed to get it out somehow but haven't got a clue how to refit the top end with the spirally bit and thread on (that sits in the spring) into the hole. Just can't seem to compress the spring enough to get the threaded top bit through the hole?

[Ginch]

I have seen people compress them with a whole lot of zip ties, just a little bit at a time.