I already have a method in my webservice that returns a byte[] containing only the bytes of the file downloading. The invocation is something like:

http://www.mysite.com/myWebservice.asmx

with:

string fileId = "123"; bytes[] fileContent = myWebservice.Download(fileId);

What I wanted to do is be able to invoke this method or other (to be made) on a aspx webpage and be able to open a browser window containing the real content of the file.

i.e. Most files are TXT and PDF. (Assuming the client has the PDF plugin that alows him\her to view PDF's on the browser.)