Not familiar with the Honda's but having just done the same job on my Son's 03' RM125, I used the outer bush to press home each oil seal. I put each seal in as far as I could by pressing with my fingers(make sure it's in squarely) then put the bush in, and cramped it up in a woodworking vice to push it home the last bit.
Remember they are performing the job more like a dust seal than an oil seal, it is under no pressure, and is there to keep the muck and water out and the grease in. Also I used waterfroof grease.
Hope this helps Sean