Automatically run exe file when tix file clicked on Internet

I have a .net program that is associated with the .tix extension. When you double click on a file it opens it in the application and handles the contents of the file. This all works fine EXCEPT when my website generates the .tix file. The user is prompted to Open or Save As. If they choose open then my program automatically opens the file and handles it fine. I have built a sample php page that generates a sample tix file. [login to view URL] Basically I want someone to create a way that can go in my installer (with helping add it into the .net installer) that will force the file to automatically open inside of my application instead of prompting the user to open or save as