Any chance you could scan a photo of the disk brake pad? If you scanned it with a measurement ruler next to it, I'm sure we can recommend pads (including part numbers and a phone number or internet site).
Australian aftermarket shops, still sell pads for almost all Datsuns.

Have a look on website http:// www.nissan.co.za (Nissan South Africa)
They will still sell Factory Nissan pads. Most likely.

Chris