How to add additional larger drives to RAID-5 array on PERC 4e/Di which is also System Drive C:?

I have a situation similar to this post: http://en.community.dell.com/support-forums/servers/f/906/p/19327594/19678204.aspx#19678204

I inherited a PowerEdge 2800, PERC 4e/Di running the following configuration:

Virt Disk 0:  RAID-5, 3 disks, 2x 33.87GB, 1x 279.38GB (only 33.87GB used for RAID)

C: drive is configured on VDisk 0 and is at about 1GB free space

Can I simply add two more same model & (Dell Ready) 279GB drives one at a time, let them sync, then span the extra space for C: using Partition Manager?

Steve