Move your cavalry and HAs to the flanks of the enemy on the hill and approach the enemy either slightly higher than them or at least on the same level. Let your HAs loose against the enemy flanks while your Cav protects them.

Your foot archers should move uphill and should be widely spaced and have them attack the enemy archers.

Use a few troops to apprach from the front (widely spaced) and then move the bulk of your forces obliquely up the hill to the sides of the enemy.

Be warned - you will take lots of casualties.

As an alternative, use HAs and try to lure the enemy down to attack you (so that you can strike them with your archers on a more even footing).

Best of luck.