SQL Server 2008 is not supported anymore. You can try to use the hibernate-community-dialects module, which contains a SQLServerLegacyDialect, that might still support older versions, but it’s like the name implies, a community supported dialect. Hibernate ORM core developers won’t invest time into that.
Your configuration seems to suggest you are using Sybase ASE though, so you might want to use the SybaseASEDialect or SybaseASELegacyDialect instead.