I can't help you 'cos' i don't know how it can works with a combo dvd/vcr. I've got a dvd player and a vcr.In this case, you must plug the dvd player directly in the vcr (not in the tv). About the vcr, you plug it into the tv. Normaly, yo won't be able to watch a dvd without using the vcr. But in this case, when you watch a dvd, to record it on tape, you just have to press the button record of your vcr. If the dvd is protected, you'll see it right away, 'cos' as soon as you press the record button, the color of you image change every 5 seconds. So if you see the image clearly, it means that the dvd is not protected.
For a combo dvd/vcr, it must be possible. Normally, you should be able to choose a channel on you vcr. The vcr has 2 maybe more auxiliary programm/channel. So try to play a dvd, at the same time, put a tape in the vcr, record and at the same time, change the programm of the vcr 'til you see the image of the dvd movie. I don't know if my explainations are clear. Maybe someone else can be clearer 'cos' english is not my mother tongue. The best thing to do is try. You can also ask someone from hi/fi shop.
I hope what i say will be useful for you.
An advice: it's better to have a dvd player separated from the vcr player 'cos' with combo, if one element is broken, everything is broken.