They're not in the editor.
This part's tricky... What you do is activate Sprite-Editing Mode in Lunar Magic, then press the Insert button. It'll bring up a dialog box with a bunch of numbers. In "Command", type the number of the sprite on the Sprite List you used, in "Screen Number" type in anything but zero ('cause some sprites won't show up if you place them on Screen 00), and in "Extra Bit", make SURE to type in "2". There are some specific sprites that you can optionally set to "3" instead, which you can see in their .asm files in the Sprites folder, but not all sprites can have a 3.
The sprite will appear, and it'll either look like a glitch or an existing Sprite. Lies!!! The sprite only looks like this in Lunar Magic. In the GAME, it should be the custom sprite you placed.
If you forget which sprites are custom and which aren't, press the 5 button. Anything that says "X2" or "X3" in the little blue box that appears on each sprite is a custom sprite. Anything with "X0" is normal.
Hope this helps. In the future, there's a special stickied thread you can post in if you have questions about SpriteTool.
High on life is the best high.