For the very moment, all our synthesizers are 32-bit only, certified to run inside 32-bit hosts, on top of 32-bit OSes. We have started heavy works to toggle all our synth line to 64-bit versions, but this will take long time before stable versions to be released.
So at this time, they may work in full 64-bit environments, or not work, depending on the hosts "bridges". The Logic one seems sympathetic (the plug-in validation must be done in forced 32-bit mode), and the Cubase one is more reluctant.
I fully agree with Phil999's statement: using a full 64-bit system still is an experiment, even these days, and should be avoided in production.