Adding keys

[Airbus_eurofighter]

Hi how can i add a key to a effect that i want??, i mean in this smoke sistem configuration:

smoke.0=0, -24.00, -1.65, fx_smoke_eng_fa18
smoke.1=0, -24.00,  1.65, fx_smoke_eng_fa18

Smoke.3=1, 0.00,   15, fx_smoke_GW_Y ,
Smoke.4=1, 0.00,   -15, fx_smoke_GW_Y ,
Smoke.5=1, 0.00,   1, fx_smoke_GW_Y ,
Smoke.6=1, 0.00,   -1, fx_smoke_GW_Y ,
Smoke.7=1, 0.00,   7.5, fx_smoke_GW_BL ,
Smoke.8=1, 0.00,   -7.5, fx_smoke_GW_BL ,

smoke.9=-0.80, -19.00, -2.25, fx_eng_exhaust_gry
smoke.10=-0.80, -19.00, 2.25, fx_eng_exhaust_gry

The first and second paragraph starts when i have the trottle over the 80% and the 3 paragraph doesnt go, how can i put that the second paragraph goes with a key and the third when i put the trottle down 10 %

Zitin