Problem with raid 1

I'm new to raid and wanted to install to WD 1TB in raid 1. I'm running Win 7 and a Gigabyte GA-MA790X-UD4 mainboard. First i had trouble installing the driver for the onboard raid controller but figured out that I needed to install a Vista driver. In bios I have set up Raid and in the raid setup I have defined an array.

Now there are two things:

1. I also have a WE 1TB sata external disk. When raid is scanning disks in at bootup it picks up this disk so I don't see it from windows. How do I solve this?

2. In win I see the tww raid disks as two seperate ones. I made a folder in one of the disks and it doesn't mirror to the other one. So I went into win disk management and used the mirror option there and now I see the two as one drive. Is this the correct way of setting it up?? I have a feeling I am mixing software and hardware raid here..

unhook the one that is single until you get everything setup then plug it back in.