SMO Backup class moved

Having worked on a (new) backup solution for my employer, I have spend several hours fighting with examples not working.
Until I found the explanation and a solution at Allen Whites blog: http://sqlblog.com/blogs/allen_white/archive/2008/12/07/loading-smo-assemblies-into-powershell.aspx

I still wonder why the the classes listed in another blog entry by Allen (http://sqlblog.com/blogs/allen_white/archive/2007/10/19/sql-2008-smo-doing-a-little-rearranging.aspx) were moved and then destroying the compability between SQL 2005 and SQL 2008...