Re: A month.
You don't - what was asked is how to add dongles to virtual machines, not how to migrate or do DR. VMWare is fancy enough that it'll attach a local USB device to a remote VM, which is certainly a neat trick. I've found Xen's USB support to be reasonably good, and KVM's to be a little less stable.
There are also remote USB over IP products, which could theoretically support fault tolerance. That's left as an exercise for the reader.