Hi Afshin,
Assuming that you have Autodesk DWF Composer (and the accompanying Autodesk DWG Viewer), you can generate multi-sheet DWFs quite easily.
With the DWG Viewer, you can use the "Publish" command on the File menu to assemble a set of DWG sheets/layouts and then publish that set of sheets to a multi-sheet DWF file. To do this, you will need to set the options in the Publish dialog to Publish to: DWF File and then in the Publish Options sub-dialog, set the DWF type to Multi-sheet DWF.
With DWF Composer, you can aggregate multiple DWF and Raster files into one multi-sheet DWF simply by dragging and dropping the files from Windows Explorer into the List or Thumbnail tabs of the Composer Navigation panel. (Note that dragging a DWF or Raster file onto the DWF Composer canvas rather than into the Navigator List or Thumbnail tabs will open that file rather than aggregating that file into the file that is currently open.)
You can also reorder sheets in Composer by dragging the sheet names or thumbnails to a different location in the Navigator List or Thumbnail tabs. Once you have assembled the sheets in the order you wish to keep, simply save the file to DWF using the Save As command.
I hope this helps. If you have any additional questions, feel free to let me know. Thanks.
Scott Lillibridge, Viewers QA
Autodesk Collaboration Services