msorrels
If you send the MIDI track with the arp to Piz's midiOUT VSTi ( http://www.thepiz.org/plugins/ ) and enable record on it's MIDI channel you can get the results of the arp. 
 
That seems to work better than it did in Hopkinton.  In Hopkinton that using the VSTI as an intermediate required selecting the track with the arp and using a virtual MIDI cable.  Now you seem to be able to record the MIDI out directly, though I may just be remembering how it worked wrong.  I'm not interested in rolling back to test it.
 
Edit: Nope, spoke too soon.  Still some oddness with not being able to direct a MIDI track to None.  There does seem to be changes here, but it's not quite usable yet.

FWIW, I tried the Piz midiChannelFilter from http://www.thepiz.org/plugins/?p=pizmidi. It loads as a 64bit synth. If you prefer to use Piz plug-ins instead of a virtual MIDI cable, I was able to record the arp from one track to another using this plug-in too.

Until the fix, here's another workaround: Use the arpeggiator MIDI plug-in, and apply MIDI effect. The plug-in isn't as cool as the track arpeggiator, but it has its merits.

Doktor Avalanche

arlen2133
So can it be played out to another MIDI track as if it were Audio???

Check the ezine.. Cheers...
http://static.cakewalk.com/cakewalk/products/sonar/release_notes/Welcome_to_the_SONAR_Ipswich_Update.pdf
 

anyone tried that yet???

As long the the plug-in can send MIDI data. Some synths can, some cannot. I describe above using one of the plug-ins from http://www.thepiz.org/plugins/?p=pizmidi. There are several plug-ins in the collection which can do the job.

"Houston, we have a problem!"
 
I have a project I'm working on now, it is an older project and it has been re-saved-as to "bring it up to date" yet no MIDI clips in it (not a single one) can be bounced down with the arpeggiator!  The "Bounce to Clip(s)" does not work for any clips/any tracks!  The Arp button turns "off" after the no-bounce bounce, but the MIDI data does not get arp'd!
 
And want to hear something else that's strange?  If I copy a clip from said project to the clipboard (i.e. Ctrl+C) and paste it into a MIDI track within a brand new "blank" template, then enable the Arp and then Bounce to Clip(s), it STILL does not work!  However, within that same blank project, if I record new data and repeat the bounce, then it works!
 
The only thing I can think of is that the project was saved during the Ipswich update and somehow the Arp-Bounce bug is embedded into the clip data.  How is this even possible?!?  That's a rhetorical question, because it's not possible...or it shouldn't be possible.
 
So what the heck?!?  This is the stuff that kills my creativity!

There continue to be new and more complex issues with MIDI data and bounce to track/bounce to clip.  And even more issues with the track arpeggiator.  I don't think it has anything to do with old projects vs new projects though.  More likely something about the MIDI data itself. 
 
Some strange things I've seen have to do with multiple clips that occupy the same time on the same track (overlapping clips).  Bounce to clip with that sitation and the arp sometimes is very broken. The rest of the issues I'm still not sure exactly what cause them. 
 
I really wish Sonar would show overlapping clips separately.  I really wish the track options/controls on MIDI tracks were fixed to be reliable and usable.  I've grown tired of the MIDI lanes in the Piano Roll View not lining up with the keys.  I can't count the number of times cut/copy/paste operations don't work right.
 
My advice on bouncing the MIDI track is to route it to a virtual midi cable and back to another track and record that.