The very best of luck to you.
I had to write a reply to your request for help on this because in a freak occurance several months ago, I had a leak coming out of my seal. I was most fortunate enough to this day to be saved by cleaning everything out very well and applying a fair amount of very thick engine assembly grease to the seal and a thin coat to the shaft.
On inserting the shaft, I twisted slowly to help "thread out" andy potential weak points - and we're talking the most minimal of effort for oil to weap through, but anything helps, right? But after that, I haven't had any oil come out and have been able to avoid a replacement of the seal.
But concerning its replacement, I really don't know how it would be done. I think there is a steel "U/bucket" ring that makes it up... ...and don't freak out on me and have a heart attack, but in order to replace it... ....I'd say that the crank case halves have to be split open. (Am I right everyone?) Or is it possible to replace that seal with out them being split? I've had a couple other Honda engines apart and seen these things, and think I remember there being minimal clearance for just a "press fit" with the seals in question.
Just my input - hope that the case doesn't need to be split though. Cause I don't know how long my "grease" job will hold up for...............