remove save and saveas from file or document of km repository

HI experts

when i assign the permission of read to a file of ms word or other file or document in km repository when i assign km navigation iview to other user.he or she is able to read,saveas the file which i give to that user in km repository but my problem is that i just want that user just see the file but not saveas the file. Is there any facility for that in portal to just see the document or file not save as well as save as to the file

please help.........