Hi Publius, I have had very stubborn seatposts on a few ocassions. My solution is to bathe (spray thoroughly) the post with WD40 for 3-4 days if necessary. With the saddle still on, wiggle it with all your might from side to side until it succumbs to your strenght! :-) If it is really tight, inclrease the WD, and wiggle some more. You may not do it on one shot, but give it your best shot throughout the day on multiple occssions. You said you used WD already, but I don't believe you were with a resolute mind to make that post release. It will work, as by looking at it does not appear to be a hopeless cause, and that you may have to resort for more drastic action. Go on prove me right! Best of luck! Very nice bike my friend! :-)
Flash