VB on Windows 8.1 - Not recognizing built-in camera

[JEB]

I have installed VB on my Lenovo laptop with a built in webcam, but the virtual machine does not recognize it.
Has anyone else had this issue and is there a solution?

[mpack]

User manual 9.7: Webcam passthrough.

[JEB]

Thanks. I am looking into that.

[JEB]

I applied the expansion pack and now it sees the webcam.
Only problem is that the cam image has 5 evenly spaced vertical bars of image with the bottom bar repeating the one above it (blinking).
I see that the manual states that you can use VBoxManage to set parameter (frame rate & max payload) when setting up a USB webcam. Is this something I can adjust with a webcam already attached?
How do I invoke the VBoxManage command line interface?

[mpack]

I'm afraid that I've never used the feature - I've never needed a webcam - so if you've read the user manual then you now know as much as I do.

[JEB]

OK. Thanks.