A Template with Transparencies

I'm trying to make a template to use as a fade filter, such as "pow", "splash" and "panda n' club" that are available at the world editor. Those templates have a invisible part, that you can see the map through and a visible part (in this case, the text). For example: the pow! fade filter. What do I do put to a transparency or a invisible part on my template so that it becomes just like those fade filters?

Thanks for help.

I suggest you open the files and check. They're in the MPQ(most likely). I'm sorry, but I don't know their names, search for *.blp