Smart Array 221 & RAID5 upgrade. How to?

[Gerardo Aguilera]

Hi,
Here's my scenario:
Proliant ML370 G1 with Smart Array 221 (no battery) and Windows 2003 Server SP1.
1) AT ARRAY LEVEL
- Array 1: 2 x 18GB. SCSI HD in RAID1
- Array 2: 4 x 9GB. SCSI HD in RAID5

2) AT WINDOWS LEVEL
- Volume C:\ 9GB from array 1. Used for Windows and applications.
- Volume E:\ 9GB from array 1. Used only for data and Exchange Server logs.
- Volume D:\ 27GB form array 2. Used for data and Exchange Server databases.

The goal is to replace the 4 9GB disk of array 2 with 3 new 36 GB disks without changes in volumes C:\ and E:\
First step is a good backup of course.
What steps should come next?
I guess I should switch off the server, take out the four 9GB disk, put the three new 36GB disks, switch on the server and start ACU from SmartStar CD to create the new array but I'm very worried about the next Windows boot up because it will not find volume D:\ neither Exchange Server.
Any tips?
Thanks in advance.