SL 2: Inserted video clip lacks controls, and slide scrubber does not sync with video content

Hi. I'm new here so hope I'm addressing this correctly. I use SL 2 and have what I hope is a simple issue (famous last words).

I've created a single slide in a new file, and on that slide I've added a 58-minute MP4 clip that is essentially a webinar replay. I have suppressed all slide controls except scrubber, but here's the problem:

The scrubber applies to the slide--not the clip. So while I can add a button to start the replay, if the user then clicks Pause or otherwise moves the slide scrubber (the only one visible), it behaves totally improperly.

1. Clicking Play again doesn't work.
2. Moving the scrubber all the way to the end advances the audio perhaps two minutes instead of the full 58 minutes.
3. Any movement of the slider puts the video frame out of sync with the audio.

This tells me that the slide controls are separate from video controls--but where are the video controls, and how does one get the user to manipulate them? The viewer should be able to grab a content scrubber and navigate backward/forward, and the video frame should properly sync with it.

Any help is greatly appreciated. Thank you!