Get user who initiates Windows Portable Device (MTP) event

I am detecting files being copied to a mobile phone, and I have IPortableDeviceValues available so I can get the file name (WPD_OBJECT_ORIGINAL_FILE_NAME) and device name (WPD_EVENT_PARAMETER_PNP_DEVICE_ID), but I'm not able to get a PSID or anything else that I can use to identify the person who performed the action.

Any ideas how I can get the user?

via Chebli Mohamed