Oberon clutch slave fitment

To make the S4R easier for my Missus to ride, I thought I'd fit an Oberon clutch slave to lighten the pull, like I have on the ST4 and Gran Canyon. The odd thing is that the clutch push-rod sticks out too far for the Oberon to clamp to the cases. The original Ducati slave (with the star-shaped end-plug) fits the rod fine, so it must mean that the outer end of the Oberon has a thicker wall, preventing the piston from retracting enough. They supply a spacer for short push-rods fitted to earlier models that show a projection of the rod less than 30mm but mine sticks out by 39mm!

I've stripped the clutch to see if the plate pack is below the proper thickness but it isn't, and the release bearing is seated OK, so the only answer I can see is that either Oberon has got it wrong for the 996 motor or someone has fitted a longer push-rod. Does this ring any bells?

The simple solution is to cut the rod down and polish the tip, hoping that the hardening is all the way through and not just the skin.

While I'm in the clutch, I've taken the opportunity to do the Quiet Clutch Mod and stop it beating itself to death and frightening the neighbours. I guess people here are familiar with this five-minute fix?

Nick