From the file name .zraw sounds like zstack in raw format. Since you can read the segmentation map already, you know the image dimensions. Use the preview version, and install the SandBox extension and try the RawImageGuess module entering the XYZ extends from your segmentation. The only unknown that will be left would be data type, but that should only take a few iterations.
Here is the thread on the RawImageGuess and a video tutorial.