I need to model a spring which has a different stiffness in compression to that in tension. How do I do it in ABAQUS?

Element defnition for the spring element :

*Element, type=Spring2, elset=Springs/Dashpots-1-spring
1, Bay1GroundFloor.5, Part-2-1.1
2, Bay1GroundFloor.7, Part-2-1.4
3, Bay1GroundFloor.8, Part-2-1.6
4, Bay1GroundFloor.3, Part-2-1.2

The spring stiffness is

*Spring, elset=Springs/Dashpots-1-spring
2, 2
**
** spring stiffness
**
7.8E+06,

By adding the nonlinear one could then define Spring behaviour which is different for compression and tension.

*Spring, elset=Springs/Dashpots-1-spring, nonlinear
2, 2
**
** Force1, Rel. Displacement-1
** Force2, Rel. Displacemnet-2
**
10.E8,  -0.1
10.E6,  -0.001
    0,   0
7.8E+06, 1.0