The 64bit Sonitus plug-ins bundled with SONAR are DirectX format. To my knowledge the VST format has never been ported to 64bit.

I'm always reaching for the Sonitus Compressor.  To me, it does the job and the interface is easily understood.  Plus it has external side-chaining ability, which is pretty sweet considering it may have been developed in 1998.  I've used the Sonitus Gate as a noise-gate, but wasn't impressed with it.  The Blue Tubes gate performed much better in that respect.  I should try the Sonitus Gate with an external sidechain.  That could be fun.  For that purpose, I use Izotope Alloy 2.

I still use my Kjaerhus stuff on a pretty regular basis - that's all 32bit but works fine - i use Jbridge and never had a problem
Nigel
 

That's right, the VST versions which we're sold for a time are 32 bit only.