thanks, good question, i hadn't looked into this yet.
Did some tests, NTSC signal into Asuka tuner AV, no problem. PAL signal into Asuka tuner AV, didnt work on Stagea S2 screen. Both worked on an aftermarket screen. So, you can pass both pal and ntsc through the Asuka AV inputs no problem, but it wont perform any conversion, it will output the same as you put in. So you would need to use a NTSC signal to get a pic on the stagea S2 factory screens from the AV inputs on the Asuka tuner or factory tuner. shame
Not a problem for aftermarket late model screens, as most/ if not all, handle NTSC and PAL.
Guess you would need a dvd player which can output in NTSC or a separate PAL-NTSC converter or reburn your DVDs to NTSC using software such as NERO.