If you visit the Captivate Exchange, you may download a
"speed control" widget there. I think what you do is to drop the
widget into a Captivate slide and configure it to run for the rest
of the project. This provides buttons (I think) that allow you to
"speed up" or "slow down" Captivate. But it's done completely
within the Captivate project itself and not from RoboHelp.
So the answer to this is that it has to be done in Captivate
before dropping it into RoboHelp. There is no functionality in
RoboHelp that allows you to adjust the playback speed in a
Captivate video you have inserted.
As far as I am aware, Captivate videos of all Captivate
versions should work with RoboHelp 7.