I am also running a VirtualBox VM with Win7 on an iMac for all sorts of Windows radio programming software: Sentinel, FreeScan, & many flavors of RT Systems ham radio programmers. My problem is that the VirtualBox VM won't let the USB pass through from the host machine to the VM to allow the radio to communicate with the software in the Windows VM and vice versa. Unfortunately, this is true for any USB device, not just radio programmer cables.
I could never find a way to get any USB device to pass through the VM to the radio programmers and finally gave up on using the iMac for radio programming except for Chirp. That's why I'm using a nearly 10+ year old laptop with Win7 to do my radio programming. I would really like to use the iMac to program my radios in some sort of VM that works.
I have heard of some people having success by using one of the other VM software choices such as VMware Fusion or Parallels. I haven't had experience with either of those. You may want to try a trial version of one of those. Be sure to read the licensing on each and make sure you can install on more than one machine.
i use crossover for sentinal and have one setup for proscan both work great but ezscan for my trx1 kept crapping out and i started pluging in the scanner before starting crossover and no problems
dont even need windows with crossover