You can use
Storage Manager for SANs
to create and manage logical unit numbers (LUNs) on both Fibre Channel and iSCSI disk storage subsystems that support Virtual Disk Service (VDS). The arrays are managed by the VDS hardware providers. The picture below illustrates how VDS communicates with the VDS hardware providers:
Storage Manager for SANs is one of the Management Applications as shown in the picture above. When Storage Manager for SANs launches, it queries the Virtual Disk Service for all the registered hardware providers. If there is no hardware providers presents on the system, Storage Manager for SANs will be disabled as it will not be able to offer any management functions.
Also, be sure about the physical connections between the server and the Array. If the logical layers are all present (indicated in the picture), but the physical layer is not connected, the communication will not be happen, and the application will be grayed out as well.