Open a NEW page in Indesign, create a picture box and Place the same image, you will see a gorgeous imported preview, the preview we all wish .ai would handle.
In order to get around the poor preview of CS5 and CS6 do this
1. From SS save a "Proof Positive" file. This is a high resolution color image of your "adjusted separated" file. Save it as a tif.
2. Open a page in .ai and PLACE that file, create your layout and show the client.
3. Once approved, using the "replace" feature in the PLACE window simply swap the color image for the separated EPS file and your are ready to make film.
4. Or, you can do as Adobe would like and use InDesign. This way the user has all the results you would expect when you PLACE the EPS file. A proper preview and full control over all elements imported, placed or opened. After all, a Publishing program exists for this very purpose, its just that most users bypass it.