It's not going to happen with paypal because of the risk of chargebacks. Read the sticky in this forum.
So if i wanna buy bitcoins with my credit card without using bank transfer, how could i do ?
You might also be able to use Bittylicious depending on what country you're in. Check them out. They're fast and simple and I recommend them.
You could also try buying coins from the forum here using western union or stuff like money packs etc.