I had some friends run into a lot of challenges trying to write a utility that converted/persisted PDF files into a SQL 2005 Database using assemblies hosted inside of SQLCLR.  Turns out they were running into a limitation in SQL I didn't know about -That SQL only suports a subset of the .NET Framework classes those NOT marked as Host Protection Attributes -regardless of marking the assembly as being "Unsafe".  After finding Tims Blog post -it still took a little while to find this in the documentation -sigh...