I hate being the Xserve Grinch. But you are dealing with technologies from vastly different generations that you are simply not going to be able to make work together. Here are some sad realities:
• Xserve 1,1 can run up to 10.7.5
• 10.7.5 will limit you to Server.app 1.0 (2.0 requires 10.8, 3.0 requires 10.9)
• Apple put custom firmware on the drives shipping in the drive modules. 2 TB drives were not a supported configuration even with the late 2009 Xserve. You chances of getting these to work in a drive sled may not be good. See here http://support.apple.com/kb/ht1219 for the official statement and here http://tidbits.com/article/10166 is a good explanation of the challenges that you face.
• Xserves (in today's perspective) are not really good at being efficient. See this http://support.apple.com/kb/HT2764 and compare it to http://support.apple.com/kb/ht3468 The power consumption max of 85W on a mini is more than doubled on an idle Xserve.
• The Xserves are just slow in terms of today's machines. From drive i/o to processor performance.
The bottom line is that if you want to build a render farm, you might want to consider a stack of Mac minis. You will benefit from faster drives, faster memory, faster processors, and the ability to run the latest OS. Assuming you are running both units at max, you can run 3 minis in the power and thermal output of 1 Xserve. These are cost savings opportunities. Plus, minis can be picked up for $599 a piece, allowing you to get 4 or more minis for the price of the Xserve.
So, bottom line. Yes, I lament the end of the Xserve. But there are just better choices.
