Thanks mr f.
With Microsoft JDBC Driver for SQL Server - sqljdbc.jar I had problems.
But with jtds they are gone.
jtds website:
http://jtds.sourceforge.net/benchTest.html
Driver can be downloaded here:
http://sourceforge.net/project/showfile ... p_id=33291
When using seam setup use:
hibernate.connection.driver_class=net.sourceforge.jtds.jdbc.Driver
hibernate.dialect=org.hibernate.dialect.SQLServerDialect
hibernate.connection.url=jdbc:jtds:<server_type>://<server>[:<port>][/<database>][;<property>=<value>[;...]]