Hi there,
So you've installed Z3TA+ 2 but you don't see it in your synth browser in SONAR? Strange. I assume you've rescanned and all that.
One possible reason for your issue: In this update we made Z3TA+ 2 a VST3 plugin, and it had previously been a VST2, so now it will show up in the VST3 folder of the synth browser.
You mentioned you have existing work using Z3TA+ 2. Are you unable to open the synth in those projects?
In SONAR there is a setting (that is on by default) that automatically updates vst2 plugins to their vst3 equivalents if detected. If you have preexisting projects with Z3TA+ 2 as a vst2, those projects should have been upgraded to VST3, and you should be able to open the synth UI by double clicking the track icon (among other methods.)
If you're still having issue, please let us know.