It should just be straightforward sequencer keyframing. For example, scrub to frame 1, set the value at 0, hit the keyframe button. Then, scrub to frame 100, set the value to 1, hit the keyframe button. Is that what you have?
It should just be straightforward sequencer keyframing. For example, scrub to frame 1, set the value at 0, hit the keyframe button. Then, scrub to frame 100, set the value to 1, hit the keyframe button. Is that what you have?