WinSCP FileMask

I've tried so many ways to get the FileMask to work with no luck. I've looked up on this forum, googled and still nothing works. Can someone please show me how to specify a FileMask for grabbing three files (all of the same extension). These three files are in a directory with many other files. Some with the same extension and some with different ones. The directory also has many subdirectories.
Any help would be appreciated :)

I can get specific files (*.lst) but I'm trying to exclude directories. I just can't get it to work.
How would you format the FileMask to grab only the *.lst files but not any directories/folders?

If you need three specific files, you do not need any mask, just call .GetFiles three times with paths to the three files.