I'm trying to use Sonar Platinum in conjunction with an Akai MPK88 for a live rig.  All I want to do is change (select) tracks with the performance pads on the MPK88.  Does anyone know how to set that up? 

Try loading each track into the Matrix view, and using MIDI learn to assign each one to a pad.

I really appreciate your response! I'm not sure what you mean. The tracks are empty (no recording) I just want to change VST instruments while playing without having to use a mouse to change tracks like changing patches with a foot switch. Am I thinking about this from the wrong angle? 
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Sorry, I misunderstood your question.  I thought you were wanting to trigger recorded audio tracks using the pads like you would a sample.
 
There is a way to set up ATC to increment and decrement plugin presets, but I've never been able to make it work with my MPK61.  Hopefully someone with more expertise will come along with a better answer on this, because I'd also like to know if it's possible.  
 
Setting the project tempo from the controller would be nice too.

Most stable solution is to change MIDI Channel in the hardware and assign each track input to specific channel. Unfortunately, changing channels on MPK is not a one button press task. So some external processor (hardware or software) is required.
 
The second approach is ACT. You can focus tracks with it and that is the way to use transport buttons. Tempo can not be changed (at least not during playback), but most other Sonar parameters are controllable. As usual, not without caveats. Standard ACT plug-ins have not direct track focusing functionality. So that is possible with my plug-in only (see the signature).
 
If you decide to use AZ Controller, after following "Quick start" (so you know how to assigned an Action list to control), the action list for pad to switch focus to track N  (0...100) is:
* 'Strip' Track <First> +N
* 'Function' "Select strip"
These 2 lines probable make no sense for you now, but after finishing "Quick start" (5-15 minutes, including reading instructions and installing the plug-in), you will know what they are.

Thank you! I will give this a try.  It seems odd to me that Sonar is not more live rig friendly. I prefer to actually play rather than trigger pre-recorded tracks. Old school I guess. I'll let you know how it works out. Thanks again!!

I have no problem setting up the knobs and sliders, but can't seem to program the buttons (pads). Am I missing something? Should I have the pads in "program change" or "note" mode? Also, shout I have them programmed in "toggle" or "note" mode. Sorry, this is new stuff for me. I've never used the pads or done any editing with the MPK88. Is there an email address where I can give my phone #? I really would appreciate the help.

Sorry, I was not checking this board last weeks.
 
If you are still interested in getting it working, please register on my site. You can PM me there (you have insufficient posts to PM on Cakewalk forum) or just create a thread in the Discussions board. Next days will be busy for me, but some short discussion on Skype/phone probably can clarify basics.