I just figured out why the seat wouldn't come off. You need to remove the two little screws first and then it comes off the way you said.Hello,
Use the key to "unlock" the rear seat portion. It is on the middle left side of your bike under the seat, the key lock that is.
After you remove the rear seat portion the front seat will come off just as the rear lip lifts from the back portion the front lip fo the forward seat portion will lift off. I made that sound harder than it is.
Fyi, you do not have to remove the seat to adjust your rear shock...(other than to get at the toolkit but that is in the rear portion.)
Who knows, your manual might be under the rear seat! I put mine there for my ride home from the dealer when I first picked up my bike.
good luck