Hi flszen,
NConstruct depends on NHibernate and the current NHibernate stable version supports only MS SQL Server up to 2005 version. There are some issues with new SQL data types (DateTime2, HierarchyId, GEOGRAPHY and FileStream) in Nhibernate which are mostly (maybe already all) solved but they are fixed for NHibernate 2.1 alpha version, which is not officialy published and probably not stable enough.
As soon NHibernate with SQL Server 2008 is available, we will release a new NConstruct version with SQL 2008 support. However, if you don't have mentioned data types in your SQL 2008 databases you can experiment with SQL 2005 Dialect. We haven't test this combination but maybe it could work well.
Regards
Thomas
NConstruct Support Team
support@nconstruct.comhttp://www.nconstruct.com