Sonar Platinum + Battery3 + PCR-800 + ACT

"Cells" are like notes, so you configure pads to send Notes. Either you configure Notes with synth expect (like AD2) or "MIDI Learn" these notes inside the synth.
 
That information is recorded into MIDI tracks. ACT is not involved. ACT is only useful to control "parameters" of a synth, what you can see/record/edit as a track automatons. But even in this case, controlling the same parameters throw MIDI CC (so, recorded into PRV as well) is simpler approach (when allowed by synth).

If you can control cells with C1-D#2 keys, then the whole question is assigning C1-D#2 keys to pads. Then there will be no difference for Battery either you use pads or keys. You can also configure to transmit on another MIDI channel or even port, that way you can play drums with pads and play something else with keys (assuming you correctly assign Inputs for tracks in questions and enable "echo" for these tracks).
 
I do not really have PCR... So I can not provide real step by step guide. But there are 2 ways:
1) (I think simplest to start with). Try to follow https://www.youtube.com/watch?v=w8zlBPuk0fY . Video is not the best, but you should be able to follow
2) use the Editor on computer. I have installed it (v2.10, for Vista, downloaded from Roland) and it looks good. You need to select correct ports in "Options /MIDI Devices...". The manual recommend "EDIROL PCR 2" for input and "EDIROL PCR" for output. Then do "Communication/Receive..." to get current configuration from PCR (there is a tip what you should do on PCR side). Once done, click on A1 and set "Channel message" "Note" etc. Once done for all pads, do "Communication/Transmit".