From the ESXi host..if you have ssh access see if you can ping using vmkping from the vmkernel port to the storage array.
By the way, I configure the iSCSI LUN unix style, I've had issues choosing vmware, give it a shot.
I have used VMware KB in the past
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1003952