There may be a setting on y our camera to set to allow it to export the video. You'd need to poke around on sony's site to see what they advise.
Another thing, the protocol for importing photos has some requirements, that all files have to be in a folder named DCIM and must have a name of 8 characters, for example DSC_1243.mov
I would suggest using a card reader instead of plugging the camera in, but I believe Sony's use their memory stick and I'm not sure if there's a lightning memory stick reader out there. Using the card reader does remove the complication of having the camera talk to the iPad. THen again, it may work fine.