To be seen by the iPad videos have to be a format it can play and follow the naming convention of an 8 letter name plus the extension
MOV_2345.mp4 for example
The files also have to be in the DCIM folder just like the photos.
As an example, your card should have a DCIM folder and in it (just making up names here as examples)
IMG_2345.jpg
IMG_2346.jpg
MOV_2354.mov
I'd put your card into a computer and see how they're named. If necessary, edit the name to become what the iPad will see and try again.
If it still doesn't see them then there may be a format issue - your camera recording in a format the ipad can't play.