How to fit footrest damper into bracket that holds the foot pegs

I have to replace the aluminium bracket that holds rider/passenger foot pegs and the gear lever on the left side. Moving the foot pegs across was easy, but behind the large nut that fixes the bracket to the swingarm there is a 'footrest damper' (part 70010391A) that is so stuck that I couldn't get it out from the old bracket. I then ordered a new one from Ducati, but now I have the problem that I can't get it into position. It goes about halfway in, but then the slot tightens (see the faint ring on the photo) and it won't go any further in.

Is there a trick to fitting this damper into the opening? Brute force doesn't seem to do it. Seems like an incredibly stupid design from Ducati, makes no sense to me.

Thanks for the suggestions. Tried grease, WD40, hammer... nothing worked. Will try to find a vice and give that a shot, or just go to my bike mechanic and let them figure it out.

Ok, a combination of heat gun and vice did the job