Inserting Active IPO on fluid inflow object. . how?

I have been trying to animate an arm and hand holding a bottle and pouring liquid from it into a bowl. I have an inflow object (filled circle) located and parented to the lip if the bottle. IPO’s for the bottle keyed with loc\rot. At frame 100 I want the inflow object to start but not before that. and to stop at frame 150. (I don’t want the fluid spilling all over the place.) Is there a way to start the simul. at frame 100? I cant figure out how to insert a curve for the “Active” param. in the Fluid simulation IPO mode. By the way, I am using 2.49b.

Start/End frame can be set from the domain object.