Flip DVD onto one sided DVD

Not sure if this has been covered, had a quick search and couldnt find the answer (which is probably staring me in the face). I have a couple of DVDs that have to be flipped over half way through in order to watch the whole movie.
How can i copy both sides onto a (single sided) blank DVD?

The software i have: DVDshrink and Nero 6.
The movies: Starship troopers and The rock
My DVD writer is the Liteon 451.

Thanks in advance…

MATT.

P.S I have only ever used DVDshrink and Nero on auto (apart from reducing the quality of menus, extras etc), I put the original into my DVD reader, and a blank in the DVD writer, and press copy disc. So my knowledge of use is limited.

Here is a place to start:

http://club.cdfreaks.com/showthread.php?s=&threadid=77124

Hope that helps.