Christmas light geeks typically use CG-1500 demarcation boxes to house the power supplies for their pixel strings. There are mounting kits you can buy, but being the cheapskate that I am, I designed a set of printable brackets. Attach them to the box of the power supply box with 4mm screws (2 per mount) and then attach the brackets to the posts in the CG-1500 with #6x1/2 self-drilling screws. I've included box STEP and IGES files in case you needed to modify them to fit your needs.