> Nevertheless, troubles arise if you have to query the historic
> table, making joins with look up tables wich reside in the main
> database.

A valid point of course, but not a problem in my case.
I don't have that many lookup tables I'd need to be duplicated.

Often enough I even don't need a duplicate lookup source, because my
applications are the only accessors to the database, and so I can
easily run a lookup against a datasource bound to a different
connection (working with ADO.net, all the really interesting stuff
happens in local RAM anyway).