I PMd ya with another link/ Almost looks like this was/is a 2 line model. Looks like a lot of ooptiions for how you want the phone to behave.

Anyway,

Here are the possibilities, depending on your model:

510A/B

R B SL/R S
-----------------
1 2 A K
L2 L1 A K


510 E/F

R B SL/R S
-----------------
1 2 A K
E1 E2 A A
L2 L1 A K
L2 L1 1 2
GN R L2 L1


I PM'd ya with a link to a schematic.