Canon 600D Bulb Ramping ISO issue

[elecstorm]

Hi, everyone! I have some troble with timelapse-shooting on Canon 600D.
I use bulb ramping for dynamic exposure. When it's become night, the shutter speed increases to 6-7 seconds.
Then increases ISO value. But ISO changes with this values only: 100, 200 and 3200. So, it can't set exposure correctly, and final result of shooting looks like this:



Bright pictures - with an ISO 3200.
It's happens always with different settings. At last time, I used 15-seconds intervalometer, bulb auto exposure value 0.02 and apperture = 3.5.
And I use the last ML version.
Can somebody suggest any ideas, why it's happening?

[elecstorm]

I found a few topics, I think, it's can help to solve my broblem:
http://www.magiclantern.fm/forum/index.php?topic=5693.0
http://www.magiclantern.fm/forum/index.php?topic=5705.0
Do I understand correctly that now one uses bulb ramping now?