??
I don't have a problem with this. In Photostream, when I press the little arrow (as if I was going to send MMS) one of the options is "Save to camera roll."
All new pictures I take end up in the photostream...that is a setting you have to enable in the camera, I believe.
Old photos do not sync to the photostream, but that is as easy as copying the older photos in the camera role to your computer and then placing them in the photostream uploads folder (if you are on a PC you need to download the iCloud client...not sure about a Mac) if you wanted them in both places.