So here's the thing...

I have a Sony XBR250 (Sony's FULL name kv36xbr250). This is a non-HDTV
and is capable of resolving a 480i input from its component inputs.
This TV has a great mode on it called the "Vertical Compression
Feature". When it receives a 16:9 wide screen image from a source (via
S-video or Component) it will automatically compress the CRT beam
vertically thereby providing a wide screen image at a higher
resolution (because it is compressing say 480 lines into the space of
what might have been something like 320 lines if the full screen were
scanned) In order to accomplish this on my DVD player, I need to set
the output "TV Type" to "16:9" and use an anamorphic DVD, of which
most are these days.

    (Just to Clarify, if I set my TV type on the DVD player to 4:3
letterbox with an anamorphic movie, I will still see a Letterboxed
image, however the beam will scan the entire 4:3 screen effectively
reproducing the black bars. If I set the DVD TV type to 16:9 and run
an Anamorphic DVD, the TV will automatically flip modes, and the Black
bars will be created not by the beam scanning the glass, but by the
LACK of the beam scanning the glass, while the actually beam will
focus all it's resolution in the Letterboxed rectangle.)

Now, in this time of Home Theater PC's (HTPC) I would love to be able
to watch my collection of movies off the hard drive or from the dvd
drive when I rent them. When I do, however (With a Component output
connection from a ATI Radeon 8500), I can only manage to get a full
screened image image in a letterbox format (IE. 4:3 Letterbox).  I'd
still like to enjoy the high quality playback that I've grown
accustomed to with my DVD player, and that means utilizing the
automatic Vertical Compression feature of my Television when dealing
with an anamorphic dvd.

So here are my questions then.
A) How does the output signal differ when a DVD player is set to 16:9
vs 4:3 "TV Type"? I realize the DVD is creating the letterbox in 4:3
mode... so more specifically: What aspect of the 16:9 output signal is
triggering the Vertical Compression feature on a television that
supports this feature?

B) (And MORE importantly) How can I make my HTPC trigger this Vertical
Compression so I can watch my Anamorphic DVDs as they were meant to be
seen?

Just a little follow up info. I'm currently using Zoomplayer as my DVD
playback software of choice due to it's extensive feature and option
set. My Video card is an ATI Radeon 8500 with VGA and S-Video out. The
component dongle is off the VGA port set at 480i and 16:9 on the
switches, but they are software override-able. I am running the ATI
Catalyst 6.1 drivers which are as of 1-18-2006. I've also purchased a
copy of Powerstrip. This is on a Windows XP Pro system.