Ian, What's the issue?
I assume you have a WRX pull type transmission and are attempting to fit a twin plate push to release clutch?

If so, the conversion mechanism is clunky and horrible.
I would suggest two options.

1/ delete the entire release mechanism, the fork, the pin, the slave cylinder etc. and set up a concentric hydraulic release bearing. It's a bit of work but worth the effort. I made the setup in 'trainwrex' if you know the car? (if not search it on here, you'll be impressed)
In Australia they are available as a replacement part for V8 Holdens, in Europe try a Saab one perhaps?

2/ Not as cool as the above option but you could re-case your transmission into a MY06 onwards Push to release 5MT gearbox case. (Ignore this option if you're using a 6MT)