I have opened a session, setup with sample rate 48kHz, imported a wave file sampled at 48kHz, set the Interpret Sample Rate to 48kHz, and loaded a VST, but still Audition keeps calling my VST plugin with 44.1kHz sample rate.
How do I change that?
Since we have no idea of what your VST plugin is, we have no idea...
Oh, I was not aware this was important, sorry.
I am developing a VST of my own, and for starters I am providing a simple pass through functionality.
Once this is working, I will add complexity.
I still don't understand, what would cause AA to provide the VST with an audio stream at 44.1kHz?
Btw, my playback device only supports 48kHz.
I'm afraid that we won't be able to help you with that - we're a U2U forum and we don't touch development stuff. Unless by some miracle somebody who actually knows happens to spot this, but I think that's unlikely. The best thing you can probably do is to visit the SDK plugin site for Audition - that's here.