I don't know what you mean by FW, nor who Peter is . If you need to do much more than have basic Ethernet traffic to and from a VM then a VF is not going to work for you.
The VF's are very light-weight interfaces that by design do little more than pass packets, especially on 1Gb devices. Newer 10G and beyond Intel devices have been adding additional SR-IOV features for VF's, however promiscous mode is not one of them and will likely not ever be one of them for security concerns. If you need more features than are available on a VF and have a requirement to run your application in a VM then your best solution is to assign the entire PF (port) to your VM.
thanx,
Patrick