I was expecting to spend a lot of time donating money to get the Sentinus since my character is a good two-shoes, but I got it on my FIRST donation, and my alignment is 3 bars into the good side. I just walked in and donated exactly 50,000 gold and I got it! Here's some screenshots for proof:
ImageShack - Hosting :: sentinusoo8.jpg ImageShack - Hosting :: 61832653bn1.jpg
Try it out and tell me if it works for you aswell...