Storage box parts

This is a box to store little parts in it which can be attached to the P3Steel frame. My frame has a thickness of 3 mm. Spaces designed for the frame at the box is 3,2mm.
There are different sizes of the boxes. The walls are 2 mm.
The sizes are:
- 110x60x40 mm
- 50x60x40 mm
- 50x40x30 mm
- 30x40x30 mm
This are the external sizes.
On the pictures you will see the first and last one.

Because I use front and back feet (http://www.thingiverse.com/thing:1284425) on the frame, all boxes don