LSL makes a steering damper for 2005-2006 990 Super Dukes that mounts on the top using the front center fuel tank mount for the frame attachment. It doesn't appear they have adjustable damping like the WP damper but it's a direct fit. You should do an internet search to see if they do have an adjustable steering damper too?
Lots of UK sources for it.
I'm in the process of adapting a 2008+ 990 Super Duke WP adjustable steering damper to my 2006 990 SD. Made an inner sleeve to move the fork clamp for the damper from under the bottom triple to under the top triple clamp and think I can use the under frame damper mount (that normally mounts to the steering stop 8mm threaded hole) to mount it on top at the fuel tank front mount like in this photo of the LSL damper.
Try LSL or wait and see if I can make the 2008 WP steering damper work.
