Programatically speaking, Vista and 7 are very similar. I know for sure that even our V5R3 worked on Vista for client access. I would imagine it would also work, though, keep in mind it will not be supported.
Hope this helps!
Windows 7 will have Windows XP mode which is a Windows XP OS running inside a VM. Your CPU has to support the correct set of instructions for this to install, but that could allow you to run what you need to as it would simply be running in a Windows XP OS at that point. That should get you through until newer software is released which runs under Windows 7 directly.