I think you should configure iSCSI initiator.
iSCSI Initiators
To access remote targets, your ESX Server host uses iSCSI initiators. Initiators transport SCSI requests and responses between the ESX Server system and the target storage device on the IP network.
ESX Server supports hardware-based and software-based iSCSI initiators:
• Hardware iSCSI initiator – A third-party host bus adapter (HBA) with the iSCSI over TCP/IP capability. This specialized iSCSI adapter is responsible for all iSCSI processing and management. Currently, ESX Server supports only QLogic QLA4010 iSCSI HBA.
• Software iSCSI initiator – A code built into VMkernel that lets your ESX Server system to connect to the iSCSI storage device through standard network adapters. The software initiator handles the iSCSI processing while communicating with the network adapter through the network stack. With the software initiator, you can use the iSCSI technology without purchasing specialized hardware.
So, use either built-in initiator or hardware initiator. Please, read "Configuring iSCSI Software Initiator" section of VMware Infrastructure 3 Online Library to enable and configure the initiator.
http://pubs.vmware.com/vi301/wwhelp/wwh ... wwhelp.htm