XFree modelines for LCD projector

Hi all,

I'm having a hard time to find the right modelines for using an external projector with my
Inspiron 5150
NVidia GeForce 4
XFree 4.3.0
Projector: Hitachi CP-X275

Visibly, I can't find the correct refresh rates (for any resolution but in particular 1024x768). I get the "swim effect" for any of the default XFree modelines and for the following ones:

Modeline "1024x768" 65 1024 1032 1176 1344 768 771 777 806 -hsync -vsync
Modeline "1024x768" 65.00 1024 1048 1184 1344 768 771 777 806 -hsync -vsync
Modeline "1024x768" 65.004 1024 1048 1184 1344 768 771 777 806 -hsync -vsync
ModeLine "1024x768" 75 1024 1036 1172 1332 768 791 797 822 -hsync -vsync
Modeline "1024x768" 75 1024 1048 1184 1328 768 771 777 806 -hsync -vsync
Modeline "1024x768" 78 1024 1046 1142 1304 768 769 772 800 +hsync +vsync
Modeline "1024x768" 78.80 1024 1040 1136 1312 768 769 772 800 +hsync +vsync
Modeline "1024x768" 79.51 1024 1056 1216 1312 768 770 786 808
Modeline "1024x768" 85 1024 1032 1152 1360 768 784 787 823
Modeline "1024x768" 98.9 1024 1056 1216 1408 768 782 788 822 -HSync -VSync

dccprobe gives:

Videocard DDC probe results
Description: NVIDIA Corporation NV34 Board - p135nz
Memory (MB): 32

Monitor DDC probe results
ID: HTC6627
Name: LCD PROJECTO
Horizontal Sync (kHZ): 31-92
Vertical Sync (HZ) : 56-120
Width (mm): 0
Height(mm): 0

Anybody can help?? The problem seems worse when the dot clock rate is higher. BTW, I have no problem using this projector when I boot my laptop in Windows.

Thanks.

AirBete.