I was also a bit worried when purchasing a back-up charger plug and data cable. The charger was fine (an iWantit travel adapter with 2.1A output if anyone in UK is interested), but I didn't realize till I got home that I'd bought a 'data' cable set. It contained a USB cable with a Mini-USB at one end and a set of 'adaptors' for LG & Samsung phones (one of which was a Micro-USB).
However, subsequent tests have proved this cable is capable of carrying a charge into the Vox, so you have to take a chance on some purchases, as the packaging didn't specifically mention it would.
EDIT: added links below.
Charger
http://www.pcworld.co.uk/gbuk/iwanti...45096-pdt.html
This isn't the exact one I got - but very similar.
http://www.amazon.com/gp/product/B00...F8&me=&seller=