creating a "broken" graid3 array?

[John Nielsen]

Is it possible to create a (degraded) graid3 array with only two (or one 
less than the planned total) providers? I'm asking since I would like to 
move from my current one-disk setup to a three-disk raid3 array, but I'd 
like the disk currently in use to be a member of the array and I don't have 
anywhere to conveniently back up the data already there. I'd like to create 
a degraded graid3 array with the two new components, copy the data from the 
current disk to the array, and then add the current disk in to the array.

If that's not a possibility, can anyone suggest a way to get the same end 
result?

Thanks,

JN