You need a bit of elastic, with a soft plastic hook on both ends. Run it from the TOP side of the soundhole to the middle of the back, and hook it on to the pickup lead there, then run the pickpup lead down the back of the guitar and twine it round the endpin inside the strap. As neat as it gets without ANY drilling of the guitar. Once decision made, then go endpin as CH says, but some pickup systems (including B-Band) are not usable with an existing endpin with a mini-jack inside, because the pre-amps are mounted on the inside of the endpin.