The iPad expects any Photos and videos to reside inside a folder named DCIM.
The files themselves must have an 8 character name plus a 3 character extension: ie image001.jpg
The iPad will then be able to read the photos and videos and offer to import them. It is the same for USB drives, and SD memory cards.
You may need to use a powered USB hub between the connection kit, and the USB drive as some USB drives will produce the "Requires too much power" message if plugged in directly.
You can use a USB flash drive & the camera connection kit.
Plug the USB flash drive into your computer & create a new folder titled DCIM. Then put your movie/photo files into the folder. The files must have a filename with exactly 8 characters long (no spaces) plus the file extension (i.e., my-movie.mov; DSCN0164.jpg).
Now plug the flash drive into the iPad using the camera connection kit. Open the Photos app, the movie/photo files should appear & you can import. (You can not export using the camera connection kit.)
Secrets of the iPad Camera Connection Kit