Softimage alembic_standinop fails to set mbkeys for later versions of Sitoa

[SaoPauloooo]

Around version 3.0 or 3.1 Sitoa's parameters for Motion Blur changed. I believe this is causing the mbkeys string to get passed to the Alembic DSO improperly

For 5 motion blur steps, I see the Operator set the end of the data string to:
&mbkeys=42.667;42.667;42.667;42.667;42.667

I believe the reference to the parameter "motion_frame_duration" in GetArnoldMotionBlurData() might be causing problems. This parameter no longer exists. There is now "motion_shutter_length" but I'm not sure it correlates 1 to 1.

Just wanted to report the issue. I'm going to look into it further when I get a chance.