you see the VM greyed out because your ESX server knows it existed but if it was in the vmfs volumet that you lost then its gone. I would right click and remove from inventory.
adding your storage should be fairly easy.
first verify you can see the storage properly under storage adapters, do a rescan on the storage adaptor associated with the disk...
then under storage try to add storage should work...
if it does not then enter into management console and run fdisk -l
identify the the disk associated with it and then use fdisk /dec/sdX (x is the disk number associated with that storage lun)
then delete the partition
do a new rescan and try to create storage again..
be carefull with the delete partition... ensure you select correct disk