I've just hit the same problem and here is how I worked around it.
The problem was to copy a database from an operational SQL Server 2008 database to a new SQL Server 2005 database.
I scripted the database using Management Studio on the 2008 server. I only scripted the database design, not the data. I should add also that the DB only has tables and indexes, so I haven't tried this with any cleverer objects although I can't think why they wouldn't work.
On the 2005 server I created a new database by hand and then ran the script to set up all the tables and indexes.
The in Management Studio back on the 2008 server I used the Export Data wizard to export the data from the 2008 server to the 2005 server. It's currently running and seems quite happy moving the data.
Once all the data is across I'll have a couple of small things left to do - create the users and set-up the security in the 2005 DB, but all-in-all it doesn't look like a bad way of doing it. It's not quite point-and-click but it's not too strenuous.
So it seems that the Copy Database wizard won't work (I think because the package ultimately runs on the 2005 server and 2005 Management Studio can't talk to 2008) but the Export Data wizard is quite happy moving data ... as long as the DB already exists on the target server.
Hope that's useful.