Add a custom file extension to Netbeans

Let me guess, for Smarty templates? I did the following

1. Open Tools and Select Options.
2. Select Miscellaneous tab.
3. Select Files sub-tab thing.
4. Click on New file extension and enter tpl.
5. Select the mime type.
6. Click OK. Done!
7. (Restart of Netbeans may be required to see the actual changes)