Hey - not sure if this is exactly it, but I just saw something when investigating Arne’s answer to another question.
Check out IAttributeList and IStreamAttributes in ivstatrributes.h; there is a note in the comment block right above the class decl for IStreamAttributes:
“or used to get the full file path of the loaded preset (if available)”
Maybe that path is part of the solution for you - but it would need to be tied to a Preset in some way to be get-able.
- Will