He gives you the National Dex.
Some certificate after you complete the National Dex.
Easy. You just have to complete the pokedex. (Not the national one.) The professor gonna give you one.
you have to complete the sinnoh pokedex the go to proffeser rowan and hill give it to you
he gives it to you in prof. rowans lab. for this you have to complete sinnoh pokedex(excluding event pokemon).
you complete the national pokedex and then talk to professor oak and he will give you it hope i helped
you have to complete the national pokedex and see professor rowan. then professor oak will come in and give you the pokeradar.
To get your second (national) pokedex you have to complete the first (sinnoh) pokedex by seeing all the Pokemon in sinnoh. when you have, go to the professors lab in sandgem town and show him the pokedex, then professor oak will come and give you the national pokedex.
It is given to you after you complete the national pokedex, just go to rowan after you see all the Pokemon in sinnoh, and he will give it to you!
When you complete the first pokedex you go to the professor's laboratory (I think that talking by the computer on hospitals also works)and he will give it to you.
After you go to the Pokemon lab for the first time, Professer Rowan will ask if you would complete the Sinnoh pokedex. Answer "Yes". He will give you the Sinnoh pokedex. If I didn't answer your question right, try Psypoke.com If you don't have Pokemon Pearl/Diamond/Platinum you can't get the Sinnoh pokedex.
First, you need to complete the Sinnoh Pokedex. Then you fly to the Fight Area and go up, towards the left side. A fisherman will give it to you.
a simple certificate