c# - Handle temporary Word documents

Question

My app creates temp documents and opens them as follows:

string tmpPath = System.IO.Path.GetTempFileName().Replace(".tmp", ".docx");
SaveDocument(tmpPath); // saves some in-memory to the tmp path so I can open it using StartProcess
StartProcess(tmpPath);

Now when users modify the docuement and leave Word, they're asked if they want to save changes - which writes changes to tmpPath.

Is there a way to tell word that this is a NEW document so that the save dialog opens the save dialog instead of overwriting the temp file?