Migrating Existing XP Install to a Promise Raid1 Config

I have an existing install of XP on a system at my brothers company. Over time the PC's importance has grown as it now runs an app that does credit card processing for the point of sale system. I want to ugprade it by installing a promise raid card. Most likely something simple like a TX2300.

I know step #1 is to install the raid card without any harddrives in order to install the drivers on the existing XP system.

The instructions are not clear what to do after that. Do I then
1) Take the existing harddrive and move it to one of the SATA ports on the card and then via the promise software mirror this to a new drive on the 2nd port on the card.
2) (after installing drives as listed above) Backup system, take a pair of new drive(of same type/model) and set up a new raid1 array and then restore the backup to the new drive array
3) Install a pair of new drives raid card, set up the new array, and some-how(either via promise software or windows mirroring) mirror the old drive that is not connected to the promise card to the array, drop the old hardrive

I assume method #2 will work but was wondering if there is a way that I can migrate without using a third party(acronis) backup and restore tool