I am the person that will be helping you today.
May I ask for you to clarify what exactly you need help with? Is your goal to watch the Apple TV as it plays videos from the iPad?
I will be standing by, looking forward to your response.
It is disheartening to hear that the Apple salesperson told you that you could do this on the Apple TV because that is not true. The Apple TV's hard drive is meant only to be used to house it's own operating system and the applications that you choose to install. If you have a smaller drive on the Apple TV, it may only be able to hold a few movies.
I know that this is not what you wanted to hear, but that is the truth. There are ways to unlock the TV that may give you the ability to try do this, but odds are that it will not work. In the process of unlocking it, you may also damage the internal Apple tv system rendering it useless.
Is there anything else that I can help with? Thank you.
If you don't want the website to give me credit for my time, I can send up the refund for you now. I have no control over the truth; I can only report it.