ML310 G5 Raid1 Drive Replace

[IET]

Posting again because I'm desperate for an answer.

Have a ProLiant ML310 G5 with Raid 1 config containing (2) 250gb drives.  One of the drives is showing "SMART failed" upon boot so I am trying to swap it out and rebuild the array.  I shut it down, replaced the drive with the same brand, speed, etc. except it is a 500gb instead.  When going into the HP Array config utility it sees the drive and I set it as a spare.  However, when going to rebuild the array it says "Array cannot be rebuilt" and then something about checking the size of the spare or something else wrong.  

I'm at the end of my sanity with this.  I originally tried swapping the bad drive out with an identical drive and it gave me the same message.  I did a full format and kept trying but no dice.  So I thought maybe the drive did not have enough space so I ordered a 500GB.  Same issue.

Can anyone give me any advice on what to do?  Any information will be helpful.  Thanks.