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(from http://www.bahneman.com/liem/photos/tricks/digital-rebel-tricks.html)
[WORKS] means this person confirmed it works, otherwise it's not tested. I 
think [NO] means it doesn't work.
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CF1: SET button func. when shooting. [WORKS]
0: Default (no function)
1: Change quality
2: Change parameters
3: Menu display
4: Image replay

CF2: Shutter release w/o CF card [WORKS]
0: Possible without CF card
1: Not possible

CF3: Flash Sync speed in Av mode [WORKS]
0: Auto
1: 1/200sec (fixed)

CF4: Shutter button / AE lock button
0: AF/AE Lock
1: AE Lock/AF
2: AF/AF lock, no AE lock
3 AE/AF, no lock 

CF5: AF-Assist Beam / Flash firing [NO]
0: Emits/Fires
1: Does not emit/Fires
2: Only ext. flash emits/Fires
3: Emits/does not fire

CF6: Exposure level increments: [WORKS]
0: 1/2-stop
1: 1/3 stop 

CF8: RAW+JPEG rec. [WORKS]
0:RAW+Small Normal
1:RAW+Small Fine
2:RAW+Medium Normal
3: RAW+Medium Fine
4:RAW+Large Normal
5:RAW+Large Fine

CF9: Bracket. sequence/auto cancel
0: 0,-,+/enable (300D default)
1: 0,-,+/disable
2: -,0,+/enable
3: -,0,+/disable 

CF10: Superimposed display
0: on
1: off

CF11: Menu button display position
0: previous(top if powered off)
1: previous
2: top

CF12: mirror lockup [WORKS]
0: disable (300D default)
1: enable 

CF14: Auto reduction of fill flash - not tested yet
0: enable (300D default)
1: disable

CF15: Shutter curtain sync [NO]
0: 1st curtain sync
1: 2nd curtain sync

CF16: Safety shift in av or tv
0: disable
1: enable

CF17: Lens af stop button function
0: af stop
1: af start
2: ae lock while metering
3: af point: m->auto/auto-ctr.
4: one shot -> <- ai servo
5: IS start