Then I add % system 'c:\Program Files\Adobe\Reader 8.0\Reader\AcroRd32.exe', 'D:\www\my.pdf'; in HTML file and load in browser.

You are doing this in your Mason file, right? This will run Acrobat on your server, not the client's machine.

++ for the trick with iframe - it works. How to use it when I return 'application/pdf' in HTTP header?

You have to create a URL which returns your PDF file. You then specify that URL as the src= parameter to the iframe. For instance, try this in the above example HTML document:

<iframe src="http://www.niso.org/publications/rp/RP-6-2008.pdf"></ifra
+me>
[download]