Kakashi is inside the Kamui dimension: http://narutobase.net/manga/Naruto/636/5
When he was warped inside it he had the cloak: http://narutobase.net/manga/Naruto/628/16
As Katsuyu stated, the cloak never dissapeared, so by now kakashi should have the same cloak all the alliance has: http://narutobase.net/manga/Naruto/644/6
Minato can use FTG with everything his chakra is touching: http://narutobase.net/manga/Naruto/644/12 (kakashi included here)
So Minato's chakra is touching Kakashi right now... so why wasn't kakashi teleported out of the dimension? BECAUSE NOW IS A MANGA FACT... FTG CAN'T GET YOU OUT OF THE KAMUI DIMENSION...
(i made this thread because i've had some arguments about this in the past)