Rename of download files

Hi,
This might not the right place to post this question as I think it might related to other languague but I’m using AS3 as my host so… The question is: is there any way to rename a download file/link to our custom name. For example: I use URLLoader to call a download link: http://www.hosting.com/my_file.mp3 then a download popup shows a save as dialog with the name my_file.mp3. Now I want the dialog to show another name that I define like my_song.mp3
in sort of my idea:
call: -download http://www.hosting.com/my_file.mp3 -saveas my_song.mp3

is this possible?