I have the same problem with picture offcenter with Panasonic plasma TV. unfortunately the problem is that Amiga composite sync signal is "pure". usually csync signal in devices such as playstation and others, need some kind of decoding. and TV takes that delay into account. Amiga (and Amstrad for eg) don't need this 'decoding' so there is no delay.
there are hardware devices to introduce this delay, they are sold on internet. iirc they are called "scart shifters" or similar:
http://ntsc-uk.domino.org/showthread.php?t=100786