Here's the one that I made.
Because it is a totally transparent GIF file, it looks totally blank. But if you right click towards the left margin between these two areas of text and choose SAVE PICTURE AS... you should see the name of the file, TRANS_INV.gif, on the pop-up. Just save it to wherever you want to use it. The Inventory folder for your AM project is where I'd put it.
Best of luck with your game.
~Cleo