How do I set up ESXi 5.1 and FreeBSD to use VMXNET 3?

I've installed the tools, but how do you get FreeBSD to work with the new VMXNET 3?  When I do the drop down in settings, the latest one shown there is VMXNET 2.  What I did find was to change ifconfig_em0 to ifconfig_vmx3f0 to use VMXNET 3.

Thanks!