Buffer while recording

Just changed out my old DVR box for a Contour box with the new software.  I used to be able to record on one channel and switch to a different channel and have the buffer preserved in the unrecorded channel.  Not anymore.  I believe this is also related to the issue of not being able to record from the beginning of a show even if it is in the buffer - it only records from the time you push the record button. These are two features that have been lost with the Contour "upgrade".  While I'm sure there are many nice new features in the Contour upgrade, it doesn't seem like there is any technical reason why this buffer functionality was lost.  Please fix this, or if there is a way to get this to work now, please let me know.