Built in Leash with Motorcable

Hi,
Does anyone have experience with a built in leash as shown in the picture.
I am thinking about building one to get my box in a backpack when travelling with my Inflatable.
I am thinking about a Dyneema Rope and just insert the cable in the core. Is that possible?
Thank you

Yes easy that works well. Feel better about having box in board though.
Insta 360 belt of ali express good way of solid waist belt to attach to body. Found it a Little dicey in big surf as Nō stretch in cable almost pulled my cable out of box few times