Rip video + Sub XML

[NoWay]

Hello,
I want to rip a video from Daisuki.net
So It's very easy for someone who know a bit how to rip.
For exemple let's take this video:
http://www.daisuki.net/anime/watch/GODEATER/Hjd
I found the key to decrypt:

<= it's that I think
I think that we can use FFmpeg but I don't know how to do it

I ripped the subs file (it's an xml file that contains all languages) so i want to know how can I convert it to .ass file )

Thanks for helping me.