Fredrik was in Arch Enemy on guitar and backing vocals from 2005-2007.
No studio recordings were made and he only appears on the 2007 EP "Revolution Begins". 
You can hear him on #4 "I Am Legend / Out For Blood (live)".

He is also on the "Live Aopcalypse" 2dvd set. Three tracks are added from the 2005 Machester Academy show.