You're using 1.2, right ? I was curious and digged through the docs again and found this in chapter 3.5 of the reference documentation:
Quote:
System-level properties can only be set manually by setting static properties of NHibernate.Cfg.Environment
class or be defined in the <nhibernate> section of the application configuration file. These properties cannot be
set using Configuration.SetProperties or be defined in the <hibernate-configuration> section of the application
configuration file.
Followed by a list of the relevant options, including dialect. According to this, I would say, your approach will not work :-(. I think the behaviour is different with 2.0, where this should be possible.