I just spent the better part of a week tracking down bugs in Mono and a custom application of mine (which I’m porting to Mono). I was having a rough time with some code working against a secure server. After reading this, this, and this, it finally works.
Bottom line: If you’re working with HttpWebRequest and trying to connect via SSL, you need to make sure that you tell System.Net to trust all certificates, especially if you’re developing a non-interactive daemon. There’s nothing more frustrating then spending hour upon hour tracking down why your code won’t work like it did under .NET, only to find out a few lines of code fixes it straightaway.