I have the same problem so if anyone has come across an earphone with a compatible jack I would love to hear from you.
The problem is that whilst the earphone jack plug will fit, the rubber around the top of the jack port is too high. This is why you need either a longer piece at the base of the earphone jack or a very narrow earphone jack (just the plastic or rubber at the top of the jack needs to be narrow) so that the jack will fit down into the hole. A small plastic jack could be filed down to fit. I'm still looking for a suitable earphone jack to be filed down. There are thousands out there.
For now I have one solution though. Here's a link to a very cheap set of earphones I bought on ebay some time ago. They give excellent sound and work perfectly.. Very clear and crisp. And cheap.
http://www.ebay.com.au/itm/In-Ear-Earphone-For-iPhone-Samsung-HTC-Remote-Mic-Headphone-Stereo-3-5mm-/322202862305?var=&hash=item4b04c982e1The top of the jack is too wide but that can be resolved by sliding off the sleeve at the top of the jack. This leaves a solid piece at the top of the jack which will easily fit down the earphone jack opening at the top of the BV6000.
I have attached a photo showing what I mean.
You just have to work the plug a little bit to get the sleeve off.
If you wanted it to look a little better you could use some heatshrink tubing but really, as it is it looks fine and is just as secure.

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