OK, I had to glue and reglue this twice to get it right (I hope). The front part of the plate is about 5mm higher than it was before. I also had to Dremel down a piece of plexiglas I had that was backing the front part of it so it was thinner. It was just getting in the way. Here it is:
Not sure if it's the same in Japan but a lot of automotive parts stores have paint mixing stations which you can get made in rattle spray cans.
In case you need a color code this is what a lot of people have been using in the past.
You may want to contact the manufacturer, I had mine for 2 years before the battery failed. The Icomm unit takes power from the amplifier and charges the internal battery, but when the battery fails it can no longer work.
Using an eternal battey means you can charge at any time or even swap the battery when the charge is too low