Removal of Shower Drain Trap

Hi Advice please
I want to replace the drain trap on my shower.
I have access to it ok and can remove the connecting pipes ok.
However its impossable to move the the old screw waste connection with the silly plastic key provided. Its in solid and need something to break the seal. Where can I find a metal key and what solvant can i use
(plusgas?) to free it up. I do not want to remove the shower tray or damage it in any way.
Thanks

Difficult to visualise what you have. Can you post a link to a pic or find something similar on the net?

Its like a 1 1/2 inch shower trap with top access McAlpine (This is the replacement unit )

http://www.mcalpineplumbing.com/productlist.asp

The top is held in place by a waste flange which is threaded and fits through the shower tray, the top has 6 castle type indents which the fitting key fits into and is used to tighten the unit up.

However the plastic fitting key is completly ineffective in removeing the old installed unit and requires a much stronger metal key.
Thanks

It sounds like someone has probably used silicone sealant to fix the flange in place. If do then you have zero chance of turning it.

You have two options:

1. Uncouple the waste pipework and rotate the trap instead of the flange.
2. Break up the flange and remove the bits.