Asteroid Watch tonight - Expert help wanted to capture it with Digital Camera

I have a very good chance of being able to view the Asteroid tonight around 8pm UK time as the weather should be clear.

I have the star walk app on my ipad so locating it will be easy enough but I want to get an image (if I can).

I want to try to take images of it with my camera but do not really now how best to try to take an image of something so faint at night.

I have a Canon 400D with a regular lens and a 300mm lens and I know the object is supposedly not going to be visible to the naked eye only with binoculars so I am assuming my long lens will allow me to see it?

Any help by anyone with good knowledge of how best to do this (if even possible) please can you help?