Headsets connected directly to a DVD player?

I would like to provide entertainment (portable DVD player) for my little
girl on long flights. She has a set of headsets. There are plugs in the
back seat to connect to the intercom.

What's the best way to have DVD sound through her headsets?

1) I could plug from the DVD into the external music but I'd have to run the
cable from the back to the front. Also, I have a 396 and would prefer to
use it in the external music plug.

2) I could get her some headphones for the DVD but that wouldn't be too cool
and it might let too much noise get by.

3) Plug her headsets directly into the DVD. This doesn't work. Is there
some way I can make that work?