Do RAID drives typically show up as Removable?

I installed three 1TB drives in a RAID 5 and have a separate drive for the OS. Everything is working properly and shows up as expected in the BIOS boot screen, however in windows (Vista 32) I now have an icon near the clock/taskbar that lists the three RAID drives as "removable". It is the same icon that is used when you plug in a USB drive to allow "the device to be safely removed".

I did a google search which turned up a similar question where the answer was to uncheck "removable drive" in the drives properties box. I don't have that check box in my drives' property box.

I'm not too concerned about this, but it doesn't seem right as these drives are not removable. Is this normal for a RAID setup? This is the first time I have used RAID.
Thanks.

Thanks for your reply.
In case anyone else has this question too, the drives are Seagate Barracuda ES.2 ST31000340NS (SATA II), they are plugged into the on-board RAID on my Gigabyte GA-EG45M-DS2H board (ICH10R). I don't see anything identifying the drives as a SCSI device if this matters (AHCI is enabled).
No need to reply again. I just wanted the assurance that everything is okay.
Thanks again