i'm not sure if this solves your problem but it might:
Code:
<property name="hibernate.query.substitutions">true 1, false 0</property>
http://www.hibernate.org/hib_docs/nhibernate/html/queryhql.html#queryhql-expressionshere is an example of mine:
Code:
<nhibernate>
...
<add key="hibernate.query.substitutions" value="true 1, false 0" />
</nhibernate>
Also, I'm not sure what you mean about SQLServer not supporting Boolean. Doesn't the "bit" datatype do it for you? That would be 1, 0, or null (personally nullable booleans give me a nervous twitch, though, so I usually give them a NOT NULL constraint...)
-devon