Is anyone able to connect Shimano Di2 SM-BCR2 to Windows inside VirtualBox on Mac OSX? I have a Shimano Di2 with the SM-BCR2 charger. Unfortunately, Shimano's e-tube software only works with Windows. I installed it in VirtualBox virtual machine and connected the SM-BCR2 to my Apple Macbook. That was a no go.

I've changed the USB port settings from USB1 to USB2 and still nothing. Windows sees the USB port but the e-tube software does not.

I've read about people using VMWare Fusion and having some luck. But also read about people using VirtualBox and having luck. Not sure why it doesn't work for me. 

Would I be better off just buying the d-fly unit (EW-WU101?) and connecting via Bluetooth through my iPhone?
A late answer, but perhaps it helps some people. I used Vmware and not VirtualBox. However: I had to disconnect and connect the usb port in VMWare, even though Windows noticed that usb was connected to Windows. Shimano DI2 disagreed. A software reconnect of usb inside VMWare fixed this.
The solution suggested about D-Fly does not fix this. I have D-Fly installed, but I needed to update and connect to DI2 wired first before wireless was possible.
SM-BCR2 charger
BT-DN110 battery
EW-WU111 d-fly unit