Failover NFS service with shared storage

I need to configure a cluster with shared storage that can be moved from Node A to Node B and vica versa. In case of failure of Node A, Node B should take over the IP address associated with the NFS service, take ownership of the shared disk, mount it and start the NFS server. I am using SUSE Linux 11.4. So far I am using the HA cluster package and NFS. NFS is sharing the drive from Node A, but if Node A goes down Node B stops working.