I'm a little frustrated that the manual says nothing about which MIDI CC the half pedaling uses. I understand that 64 is the sustain of course, but the half pedaling operates at a different location...??
Half pedaling is via cc64. In the current version half pedaling affects the sustain resonance, but does not change the decay rate of the main note. The update version 1.05 is nearing release and includes half pedaling improvements, so that fractional positions of sustain (aka half pedaling) change the decay rate of the main note. Most likely this will be more noticeable to you than the sustain resonance.
The sustain resonance is very noticeable and definitely is a factor that makes this piano sound so much closer to real than any other sampled piano I've heard. I guess though, I am wondering how to make it change values throughout the course of the composition, just like a pianist would press down the pedal to varying degrees. Or is that what you are saying is included in the update?
The sustain resonance already does that - I think what you're looking for is more likely to be accomplished in a technical sense by elongating the decay rate of the note depending on cc64 position, and that's part of the update. It might be easiest just to say that you'll probably like v1.05 if you are looking for half pedaling improvement.
So, is there a recommendation on which actual pedal I should use on my keyboard to accomplish half-pedaling in Steinway?
A standard sustain pedal might not give you half pedalling capabilities. There are sustain pedals which spit out continuous data which is what you will need, instead of a pedal that only functions as an on-off switch.
I don't use a "real" sustain pedal in my piano music since I enter each note one by one in the staff view with my mouse. How could I do half-pedalling in this manner? At the present time, CC64 doesn't work for the half-pedal function. Which CC would I use?
You would use cc64. You would also need to have the sustain resonance feature turned on. But see my first response in this thread for why you still might not perceive as much of the effect as you were looking for, and for why the coming update might help.