If you can get past the parcel shelf (which IS possible with a little patience) you can pull the seat releases and get the back seat down.
Once in to the boot you can remove the fixings from the inner plastic trim panels and get behind them to access the boot release. It has a metal wire/cable going to it which you need to pull to release the boot.
It is possible to do as I've had to do it...
EDIT:
Have a look at Barrys thread to get an idea of what to look for...
One last thing (and because I almost did this) when you tried it last, was the engine running? I almost ordered one up before I realised that the solenoid only works when the engine is off!