TPYLE,
My description will not be clear - sorry - but I will try.
[this post has been corrected, after I looked at my spare latch/lock/door)
Look at the edge of the door on the latch side (not the hinge side). You will see the end of a piece of metal plate that is inserted/slid into the door to hold the lock mechansim in place. Use a lot of penetrating oil because the plate will be rusted and hard to slide out.
After you slide this retainer plate out, the lock mechanism will come out. Then you can get the latch out.
I have a spare lock/latch mechanism in a spare door and will post a few photos this evening.
Tim