Anti-blanka roll attack help (CC)

I watched the video. I tried doing the CC after blocking the roll attack but i can never get the first hit to land. It might be my timiing from activating the CC, but I don’t think that is it. Maybe i’m not executing the qcb+jap quick enough.

Here’s the link to the video:
http://www.namonaki.com/games/antiblanka.html

Any tips appreciated.