No, as the fetch logic in hte O/R mapper core is generic code for all databases, and this requires a specific piece of code especially for sqlserver 2008.
If you want to store hierarchies in a database, you can do that with several different methods, e.g. the CELKO way with balanced trees or with precalculated tables with parent-child pairs.
The 4 datatypes added to sqlserver are supported btw.