I explored, and find the way.
I have to input the Camera gain under the equipment profile here:
And when I apply the profile to the sequence, this "139" value will be carried to the Control Panel, and when the exposure starts, this value in the Control Panel will replace the ASI ASCOM driver to set the gain.
It looks there is no effect, on whatever I input into the e-/ADU both in the equipment profile and control panel.
There is a choice of "Link Cam" but I do not understand the implication of this option.
As in the help file point out, offset is not supported in ASCOM 6.2, thus I have to set it in the ASI ASCOM driver, even I am running ASCOM 6.3.
I hope the developers can give us some more hints how these fields should be set.