I am unsure with other DVD players, but with mine, if I allow the DVD to record until it is full, it will automatically finalise.
On the DVD player, bring up the disc menu to see how much time you have left of recording then, if you don't want to add anything else to the disc, go to a blank channel and record that.
Try this and keeps fingers crossed. Hope this helps and good luck!!!
Kelly R, February 2008