occide
I needed an instrument track with a VSTi that additionally outputs it's MIDI to another track.

This will only happen if the VSTi supports it. Moreover, starting with X3, "Enable MIDI Output" by default is enabled for synth that support it. Adding an instrument track using the Add Track button does this automatically like all the other synth add options. This is one reason referring to old documentation is not a good idea. FWIW, removing the old version from the URL does resolve to the current page albeit not in English. I have to change the language to 3 in the URL to display the English page.
 
It might be a good idea to provide more detail about what the desired result is. I suspect this will be a case of cloning the MIDI data or using a virtual MIDI cable to drive multiple synths. But this is just a guess because the OP has not clearly stated what purpose of the exercise is.

The Synth Rack seems to be the only way you can change the option, after the synth has been inserted into the project.  The VST options in the plugin interface seem to stay greyed out, no matter what.
 
In addition, it seems to be dependent on how the individual VST is designed.  Just to try this out, I inserted Addictive Drums 2, Strike 2, Session Drummer 3, and SI Drums into a new project. 
 
From the Synth Rack, the Addictive Drums and Strike were still greyed out, but the other two were accessible.
 
http://www.cakewalk.com/D...elp=SoftSynths.19.html

Could someone post a known working example of using Midi Output - preferably using Cakewalk plugins.  I'd like to recreate it.  For instance, I thought I could send a pattern playing in Session Drummer to Addictive Drums but it's not working.

craigr68
Could someone post a known working example of using Midi Output - preferably using Cakewalk plugins.  I'd like to recreate it.  For instance, I thought I could send a pattern playing in Session Drummer to Addictive Drums but it's not working.

Although Session Drummer seems to have a MIDI output I can't get it to work either.
 
Try this thingy.. http://thepiz.org/plugins/?p=midiChordAnalyzer
It's neat and fun :D
Just route the output of the snake to your favourite synth. Activate the monitoring symbol on the synth.
Pin the snake. Play your keyboard on the snake channel.

MIDI Out can be enabled even for synths that don't support it. Session Drummer does not send MIDI Out, and I don't know of any SONAR-bundled synths that do.
 
One oddity to be aware of with MIDI-generating plugins: I believe it's still the case that in order for MIDI Out to be active, you have to to have an audio track with input assigned to an audio ouput of the plugin even if you're not using it.

From Sonar X3 Power
 
"SOFT SYNTH MIDI OUTPUT:  While all soft synths must provide at least one audio output so that you can hear and record their sounds, some also provide MIDI output.  This output can come from a built-in arpeggiator (melody generator) or some other feature provided by the soft synth. By activating the Enable MIDI Output option, you can record the MIDI data from the soft synth into SONAR for editing."