WARNING - You will have to permanently modify the dualshock in order to make this fit. You need to snip away the middle "cross" of where the DPad is inserted.

Use any of the XBOX One magnetic DPAD adapters on a Dualshock 4 controller.

I use this one:

https://www.amazon.com/gp/product/B01I1G6R9M/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

I reused the magnets that came with it.