Enderportal issue

Hello!
When I for not a long time a go tested the version 1.9 pre release 2, I discovered that the enderportal wont work!
First I tried to get the blocks in creative mode and built a portal by that, it wouldn't work. (5x5 block portal, without a block or the edges.)
Then.. I tried finding a portal and when I found it, I tried that one too.. would it work? nop..
Before the final release, could you possible fix that?
Thanks!

Best regards, olesien