Hi guys,

dB audioware has just released 2 plugs, but it is possible to use the sidechaining features in Nuendo/Cubase.

Here are some tutorials:
http://www.audiocourses.com/article1752.html
http://www.audiocourses.com/article1748.html
1 for sidechaining a compressor, and the other for a gate.
For sure, plugin should be capable of sidechaining. And luckily there are more than couple of 'em.