Upgrading an existing RAID 10 array

Hi all. I have a RAID 10 setup on an ICH9R chipset (ASUS P5K-E motherboard). It has four identical 320GB drives for a total of 640GB usable space. I have it partitioned into an 80GB partition and a 560GB partition. (All numbers are approximate.)

I would like to upgrade the array to 1TB drives, creating a new 2TB of virtual space. I do not have another ICH9R-based motherboard to use as a setup vehicle, so I figure that I will need to do the upgrade in-place. Here's my idea:

1. Determine which drives are used for which half of the mirror set, based on serial numbers.
2. Remove two of the 320GB drives, leaving two that have unique data.
3. Confirm that the remaining 320GB drives function together in degraded mode.
4. Replace the removed drives with two of the new 1TB drives.
5. Tell the ICH BIOS to restore the array to the new 1TB drives.
6. Remove the remaining two 320GB drives.
7. Confirm that the new 1TB drives function in degraded mode.
8. Add the remaining two 1TB drives.
9. Again, tell ICH to restore the array to the new 1TB drives.
10. Tell ICH to expand the array to fill the 2TB drive set.
11. Use gparted to resize the 560GB partition to fill the empty space.

Is there any reason this process would fail? Is there a better approach? Step 10 is actually the one I'm least sure about - does the ICH BIOS or the Matrix software support expanding an existing array to fill empty space?

Thanks in advance.