How To Remove Stromer License Plate

[Rincon]

I removed the top half of the Stromer ST2 license plate holder, but I can't figure out how to remove the bottom half. Any suggestions?

 

[Streumer]

Look at the inside of the fender and you will see how it works, better visible at the front fender.
In this weather maybe you have to clean the inner part to see.
2 nothes to free. I got it of for my homemade rear light integrated in the upper part.