Removing a strut insert

[Radek]

Hi Guys!
It's a 90Q, 1988 - the shock (front) has probably been there for the last 23 years!  So far, managed to undo the big nut holding the insert in place (channel locks and some help from a pneumatic hammer), but the shock is virtually welded inside the housing.  Bentley says to put a nut on the piston rod, hold it with a wrench and hammer it out - ha ha!  No amount of pounding will make it budge.  Right now it's soaking in PB Blater overnight.  
Any tricks you can suggest - I was thinking of drilling a hole in the bottom to put more PB Blaster, but that would put a permanent hole in the housing - probably not a good thing.  Ideas?
TIA
Radek
Ottawa, Canada.