Thanks to all who chimed in. I'm sure this forum will prove very useful to a new tractor owner like me!
Rick did stop by yesterday; I had it all wrong, the short square adapter shaft is not intended to be removed (right on the money, loulblades), and once Rick said to look at the rear of the driveshaft extension, I quickly located and operated the quick disconnect there. So, I was way off in my newbie understanding of how things work....
On the bright side, I successfully removed the FEL and re-attached the snowblower, then proceeded to attack icy build-ups on the side of my dirt road where my driveway connects and around the lower driveway & house. I have to agree with the gentleman from Maine-- this thing easily throws snow 60-70 feet, even the large ice-laden chunks I was breaking up! I will use it on our new snow (about 5") later today, which should be a piece of cake for this tractor/blower. I am really impressed with this thing's ability!