how to physically attach a junction box to the back of the panel.

[bucksy]

I have encapsulated my first panel with 2 wires from the ends of the +/- bus wires.
How does one now attach the junction box to it.
I was playing with the idea of connecting the cables to the box. taping them down flat and using a thin second layer of epoxy to hold everything in place.

BTW what would be a good finish for the backside of the panel?

Thanks for any input.