Exporting Georefenced PDFs ArcGIS desktop 9.3

I am using ArcGIs v 9.3. I want export PDF maps in georeferenced PDFs. Earlier I knew that there is an advanced option in file>export map>options>advanced. Where I have to enable export map georeference information. But when I am going to export following above said I can't find (export map georeference information ) in advanced option. So please suggest me what to do now?or what is the problem? Awaiting for early reply.