Little preseed problems

Hi

I'm trying a preseeded Lenny 5.0.1 installation and some options are skipped and the defaults are selected.
Please can you help me with any? The options skipped are:

1 ) cdrom-checker doesn't start with "d-i cdrom-checker/start boolean true"
2 ) OEM installation doesn't works with "d-i oem-config/enable boolean true".
3 ) Xorg configuration are the default, and this preseeds are skipped:
"xserver-xorg xserver-xorg/autodetect_video_card boolean true"
"xserver-xorg xserver-xorg/autodetect_monitor boolean false"
"xserver-xorg xserver-xorg/config/monitor/selection-method select"
"xserver-xorg xserver-xorg/config/monitor/mode-list select 640x480 @ 60 Hz"
"xserver-xorg xserver-xorg/config/display/modes multiselect 640x480"
"xserver-xorg xserver-xorg/autodetect_mouse boolean true"

I attach the complete preseed file for any questions.I don't know if any of this preseeds are not supported, sintax are correct or any additional preseed are needed.
Sorry for my English and thanks a lot in advance