Recording volume changes

I've recently downloaded some MIDI-Hits song files, and I'm trying to re-learn how to record volume changes. Since I couldn't do it in these files, I decided to do something even simpler. I started with a new template, and just recorded MIDI date for about 2 measures of 1 track. I then went back and was able to hear that MIDI track play my synth. Then, after again arming that track for recording, I lowered the volume as it was playing, by using the inspector view to gradually lower the volume all the way to zero. 
I then went back to the beginning, and put the volume back to 100, since it hadn't gone up by itself. However, as I again listened to the track in play mode, the volume did not go down. In fact, when I went to Edit to try to Undo the recording (volume change) process that I had just done, the "undo" word was in a faded appearance, meaning I couldn't even undo anything--obviously because there was nothing to "undo."
Thus, my question is: isn't that something I should be easily able to do, and, if so, does anyone have any ideas what I'm doing wrong?
 
Thanks
 
Not to be too greedy, but I'd also like to know if there are any updates for Sonar 8.5  Producer. I'm asking because I was trying to import some instrument definition files, and my Sonar program doesn't seem to have Kronos or even Motif. Perhaps Cakewalk doesn't offer updates, since they mainly just want people to update to newer Versions. I'm not just even talking about the instrument definition files themselves. I can't even figure out how to have the name of my synth, such as Yamaha Motif or Korg Kronos, show up in the Options/Instruments/(output/channel right column destination file name, under the title,  "Uses Instrument,")
 
 
Thanks. An answer to either question would be much appreciated.
Larry N
 

 Adding volume is as easy as brundlefly says but first go to the events list and remove any the original volume controllers or they might override yours. 

ha!.....a question i could almost answer!
but instead i'll answer with another question  ;)
 
 
as this was my own issue not too long ago i've since used "insert envelope" or whatever and manually typed in the amounts
 
it's no difference at all if i were to just move the slider on the mixer board correct?
just write automation on and it's the same thing as inserting an envelope except the power is a bit more in my hands?

Yep as he said, I used to do it using the W and playing the whole song etc and this works like my old Yamaha digital mixer does via midi. So I was used to automated mixes going way back to an Atari system. But once I learned to manually insert nodes I have not used the W record feature since. The W rec method results in a million nodes which is a bit (lot) harder to edit. I find adding nodes manually is much easier to edit any changes later on as there are way less node points to deal with. .