I posted a similar message to the Native Instruments forum, but I'm cross posting here because the Sonar community is helpful and knowledgeable (the NI folks, not as good).
 
I am likely making a novice mistake, but editing MIDI for Battery 3 is driving me nuts at the moment.
 
I loaded the jazz brushes kit into Battery, then dropped a MIDI loop into a track. The loop (which has the right timing) was hitting note D3. When I run the loop, the D3 note plays. So far, so good.
 
But I want C1, not D3. And I know C1 works because when I hit that on the keyboard, I get the correct drum strike.
 
But C1 in a MIDI track does not play on Battery. If I edit the D3 note to be C1, the meters in the MIDI track jump, but not the meters in the Battery track or synth. If I add a C1 to the same loop, D3 still plays but C1 is silent.
 
Any help is appreciated. 

I had a similar problem a while ago. Make sure you set the buffer to 500ms in midi preferences. If you are using LP MB or LP EQ plugins, turn their precision (Expert) to non-linear until you are ready to print/export. Hope that helps.

Thanks 35mm. Sadly, that did not fox the problem. I changed the playback buffer spec (the only one I found umder MIDI preferences). Not using any plugins.

How many keys is your keyboard? I have a 25-key Impulse and when it comes to mapping keys to specific drums (in my case, Addictive Drums), I have to sometimes shift the zone of my keyboard to make sure the active key range extends over the key mapped to the kit piece I want. In your case, the C1 key to the drum your trying to trigger.

Hope this helps.

Thanks Billy86.
The keyboard is not the problem. I can hit C1 there and the correct drum plays. This indicates that Battery is listening to the omni channel correctly.
The defect then is in the Sonar midi track and the delivery of the C1 note.
Last night, on a hunch, I created a new midi track and drew a C1 note into it (bypassing loops and such). Same problem ... the note clearly plays in the midi track (meters jump) but not in the Battery synth (no meter action).

There is no standard for MIDI octave numbering. By default, middle C (note number 60) in SONAR is C5. This can be changed if desired, but the simplest solutions will be to the notes to C3. Most drum synths have a Kick on note number 36.