"We have successfully tested that after unloading AppleFWOHCI.kext the current tools won't work anymore."
If that's true then an option for those who need to use FW/TB devices is to remove the drivers from the system folder to prevent loading at startup and kextload/kextunload on demand.
The following named drivers are present in "/System/Library/Extensions/" :
IOFireWireAVC.kext
IOFireWireFamily.kext //(The AppleFWOHCI.kext mentioned above is included here)
IOFireWireIP.kext
IOFireWireSBP2.kext
IOFireWireSerialBusProtocolTransport.kext