Someone seems to share my view on this.LOL what? Naruto created a new seal. If he didn't then how the heck did that new seal appear inside naruto to trap the kyuubi? The manga clearly shows this, the chapter title is even "A New Seal." Naruto performed the entire seal, there is no proof that he only performed part of itt.
And yes besides this naruto hasn't shown any sealing jutsu of his own, but considering he can perform a sealing jutsu at the level beyond minato, it is highly likely that he can perform minatos and jiraiya's sealing jutsus as well.
The only way I can see it otherwise is for Kushina to give assistant somehow without we being shownU_U