Alternatively, if the OP in Philadelphia has access to a 3D printer, I produced a design for the bracket - see this post:
https://z4-forum.com/forum/viewtopic.php?f=2&t=124554&p=1776581&hilit=first+aid+box+bracket#p1776581
Here's a ZIP file containing the STL files: E85 First Aid Box Bracket.zip
It's a complex shape, so to avoid the need for loads of supports it consists of the base plus the the three pillars which just bolt onto the base - see the photo in my original post.