Q: Adding a client machine...

If I install OSX 10.7 on the client machine, will it be able to mount an xsan volume hosted by OSX 10.6.4 servers?

I have 2 xserve's and a mac mini running OSX Server 10.6.4 as the controllers of an xsan volume, and 4 Mac Pro's connected to the xsan volume via fibre network with multiple computers connected on the ethernet network.

Now with the launch of OSX Lion Server, I cannot purchase a license for Xsan 2, and I need to add a 5th computer on to the fibre network. Is this possible without upgrading the controller machines to OSX Lion, and will the client, having a later version of the OS, conflict with the controllers?