I've never used it myself, but I guess that you may use NeroInitImageRecorder to initialize the image recorder.
Furthermore, NERO_SCSI_DEVICE_INFO::nsdiCapabilities has set the flag NSDI_IMAGE_RECORDER in the list of devices, so the image recorder should be easy to find in the collection returned by NeroGetAvailableDrivesEx.
Finally there is an DLG_FILESEL_IMAGE enum for the user callback dialog which can be used to set the image path.
So I would guess you
1) Get the drives collection by NeroGetAvailableDrivesEx
2) Find the image recorder in the drives collection.
3) Init the image recorder by NeroInitImageRecorder (is this really necessary?)
4) Maybe handle the UserDlg callback DLG_FILESEL_IMAGE and provide the path for the image file
5) Burn the compilation to the image recorder.