From my previous experiences of installation of RS 2005, you have to recreate the database for RS to work in Sharepoint Integrated mode.

I am in the process of upgrading my RS from 2005 to 2008, which i will begin to work on tomorrow.

The only reason i can think of for the DB to to flip to Native mode in Nikolas case is the copy process, but that shouldn't change the schema, so, it baffles me.

I will update you all, how the process went.