How to mount a Sanwa JLF to metal panel (inside)


Just got 2 JLF stick to build a 2 players arcade stick. I want to use a metal panel.

I noticed that the mounting plate in the JLF is flat. I don’t want the screws coming out of the pane.
I see that my Madcatz TE stick have some kind of spacer soldered to the panel and the JLF is mounted to the spacer
so that the screws do not protrudes to the outside of the metal panel where my art is going to be.

See the spacer here (google picture)

Where can I buy the spacer or how can I mount The JLF to the metal panel without the screws coming out of the panel.