Yeah, so don't do this... not if you have more than one log file anyway. Took me a couple of hours or so to find how to rebuild a logfile from scratch after trying this "solution," as the db would not attach without the log files present.

For others who find themselves up a creek as a result of trying this, see cchitanu's fix here --

http://qa.sqlservercentral.com/forums/shwmessage.aspx?forumid=5&messageid=18193&p=2