Hi,
Incase if you destroy RAID you will loose all the Data, so prior to destroying RAID, move all the VM's to a Shared Storage it can be a NAS or SAN. Incase of non availability of NAS & SAN, do a VI client to the ESX host from a Machine on which you have space available equivalent to the Space occupied by all the VM's on the current datastore. once you have VI client session to the host, Browse the Datastore and download the VM's to the Local Drive of your VI Client Machine.
(Note: Remove All the VM's from Inventory before Destroying the old RAID or Datastore)
Once you have replaced all the disks with new disks, create the RAID again, boot the Host, create VMFS datastore.
Now again do a VI client to the host, Browse the newly created datastore, this time upload all the VM's which were downloaded earlier.
Once all the VM's are uploaded Browse the datastore and go the folder of each VM, one by one. you will see a file wityh extension VMX, right click on the file and select "Add To Inventory". A wizard will appear follow the wizard and you are good to go.
Regards