Thanks!
It works in PDFXChange Viewer (free). 
http://www.tracker-software.com/prod...xchange-viewer
It is possible to flatten pdf in free version and than print it (or print it to virtual pdf printer, if you want to have it in pdf). If you save flattened pdf, DEMO watermark is inserted. If you print it (to printer or pdf) before saving, there is no watermark.