Are you having issues getting the seal over the shaft or in the bore?
The fitting over the shaft should be quite easy - it's a sealing lip that is flexible.
The fitting in the bore is actually rather tight and the seal is quite difficult to get in - but I never would suggest to grease the fitting of any seal in it's fitting bore.
The seal needs to stick in it's position with a dry, non lubricated fit. You could eventually try to use a little bit of fuel applied to the outer diameter of the seal, as some fuel will make it slippery at the start and then evaporate, leaving the seal with no lubrication once fitted. But you would have to be quite quick in applying the seal before the fuel actually evaporates. Having done this operation a few months ago, I don't think that is possible. But you could give it a try.

Long story short. I used a socket with the right diameter to push (hammering is not a option, it destroys the seal) the seal in place. Used a lever against the drive shaft to get enough force to push it in -> so the drive shaft in place comes in actually quite handy for the fitting process.

Good luck!