Adding/Modify audio parameters at runtime (AudioProcessorValueTreeState)

I am working with a custom VST host on a headless system (so no GUI to control the plugins). In order to properly control my audio plugin, I use audio parameters, but I need to add or to modify these audio parameters after the construction of the AudioProcessor. Is there any way to do this?

For example, my VST plugin scans several directories on my system for audio files to work with. I would like to add these files to the selection of an AudioParameterChoice in my AudioProcessorValueTreeState at runtime, but I cant find a workaround for that.

I am grateful for any help!