I need to do the same thing with a 1991 Legacy Sedan. I found a YouTube video that makes it look pretty simple to remove:
...and one on re-keying a cylinder lock:
so, between the videos and the spare ignition cylinder from my '98 Forester, I figured I could make it work. Nope. As mdjdc says...
For example, the "trick" to remove the lock cylinder from the housing doesn't even work on the Forester assembly. So, after the head gasket is finished on the Legacy... off to the junkyard for ignition cylinders w/keys. Fortunately for me, Subarus are plentiful in the NW.
Hope this helps someone..