Do you have any suggestions on how I can help him see the ramp as friendly so he will try to go up and down it?

i had to train my pup to walk down a ramp to a ferry we have to use on a regular basis ... i started by standing on the ramp myself, and keeping tension on the leash ... i did not talk too much, the occasional verbal encouragement, and if he made any move forward i praised him up and left to try again the next day ... by the fourth day he walked down the ramp ... and now he will run down that ramp :O) keep a little tension on the leash, not pulling the dog, but tension, and any move forward, immediately release tension and praise (verbal or food) and keep trying ... you have to be calm and patient, never frustrated or angry and not too much talking ...

If he responds well to treats, use treats in the following exercise. If he's an attention responder, just use praise and petting.

Sit on the ramp, at the bottom end (with him below the stairs), and call him over. Reward him. Repeat until he doesn't seem to even notice the ramp.

Move up so that he has to put his head over the ramp (but no feet on the ramp) and repeat.

Move up so he has to put a foot on the ramp to reach the reward/treat, and repeat.

Move up so he has to put both front feet on the ramp.

If this sequence gets broken, and he won't progress, change tactics. Cover the entire stairs with stuff so he can't use it.

Sit at the top of the ramp, with him on the lower level. Don't call him or anything - just sit and wait for him to decide to come to you. Bring a book and a snack - you may have to wait an hour.