On November 29, 2005, Cassini shot a nice sequence from an "encounter" of Janus and Epimetheus. In this sequence also appear few stars - two brighter and three quite faint. But first I was only stumbled across one of the brighter in this GIF animation: http://www.greuti.ch/cassini/fb_epimetheus_n00043503-36.gif (large file (1,4 MB))
Tilmann was able to identify this spot as UCAC2-30620769 (or HD 217167)
So it was easy to find a picture of the starfield where the two moons of Saturn were in front of at this time - and to make a nice (fictive) animation with the cutted moons: (500 KB) http://www.greuti.ch/cassini/epimetheus_janus_starfield.gif
To show how exact the orientation could be, additionally two images that show the position of the visible stars in the Cassini pictures at the beginning and at the end of the GIF animation (each time the entire picture/frame of Cassini overlay (30% transparent) the picture of the starfield):
http://www.greuti.ch/cassini/epimetheus_ja...eld_marked2.jpg
http://www.greuti.ch/cassini/epimetheus_ja...ield_marked.jpg
Nico (SigurRosFan) still made a nice picture of it with some labeled features of the starfield: