VMWARE ESXi and ACU

[WFPL4E]

I have an HP BL680C and other production servers using 2 X 146GB SAS drives in RAID 1, on which I installed VMWARE ESXi. Running short of disk space, I rebuilt my Array with 300GB SAS drives. So far, everything is working fine, I did not have to interrupt my production software, but the problem is that I do not know how to expand my Array to 300GB? – How can I install the ACU Software and expand the Array without shutting down my servers? (I have done the same thing on Windows and it was very smooth, I hope I can do the same with VMWARE ESXi. Please advise