Image Source, NASA STEREO.
On August 1, NASA rolled the STEREO Behind space craft and took a series of images out towards the constellation of Orion.
Even with the short imaging time of around an hour, comet Elenin was picked up as a fuzzy dot in the wide-field H2 instrument.
The spacecraft will undergo this series of rolls for about a week, when Elenin enters the nominal field of view of the higher resolution H1 instrument.
See the STEREO site for more details and animations, and Leonid Elenin has a nice GIF animation of his comet in STEREO.