The answer is called Echo Fire.

it's a software app. for moving QT from any app. that supports QT out through the firewire cable.
Check it out here:
http://www.synthetic-ap.com/products/echofire/

they made it for using in After Effects/Photoshop, but I discovered it works fine in Pro Tools LE.
just have the DV film (as in full quality DV) on an other HD than the audio (I use a FW HD).

after installing EF go to preferences and "put in" PT as an app. (actully is all ready there in the list)
Import your DV film into PT (and import the audio from your film if needed. Important: after importing audio from the Dv film, in order to get "it" to sync with the film you need to offset it, approx 120-180 msec. audio will play from the LE soundcard and DV via the FW), connect a DV camera to the computer and then . .

what I do is this:
I connect a DV camera/player to the computer, then from the camera I go video out to a VCR, from the VCR I go via the SCART cable to a TV monitor for myself and via the antenna output to a TV monitor for the actor doing overdubs. Works like a dream.

One needs to "hide" the QT window in PT, it doesn't show anything but it's in the way. I drag it down below all open windows.