Once the barrel comes out, be careful. The only thing holding the catch into the lock housing is a small spring. Lose this and you will be buying a new lock.
Henway...
I cleaned/lubricated the inside of the PX lock housing with Tri-Flow Superior Lubricant. Several locksmithing sites recommended this stuff over WD-40 or graphite, plus I found it at my local hardware store.
With the key in, I slid the LML lock barrel into the PX housing, and after a few wiggles, I heard the retaining tumble/tang snap into place. I was quite relieved as I was not sure that LML tolerances would be the same as Piaggio, but in this case, everything worked out.
Now I have a lock that works and looks great, without the hassle of an extra key.
Now to get my hands on a chrome seat lock...
