I configure this T42p with SaX2 as follows:

- SaX detects the internal display to be a 1600x1200@75Hz
- I select secondary output
- I configure VGA 1280x1024@75Hz, max resolution 1280x1024 as secondary output

Now the screen section is only configured for 1600x1200, and the modelines
section appearantly does not include correct modelines for e.g. 1024x768.

This changes as soon as I

- Select Monitor/Change
- Simply press OK (that is: acknowledge the already correctly set monitor).

Now everything works as anticipated.
Configs & Logs follow.


Diffs of configuration:

--- xorg_conf_bad       2005-08-15 18:14:28.758317031 +0200
+++ xorg_conf_ok        2005-08-15 18:14:28.761316508 +0200
@@ -1,6 +1,6 @@
 # /.../
 # SaX generated X11 config file
-# Created on: 2005-08-15T18:13:11+0200.
+# Created on: 2005-08-15T18:07:50+0200.
 #
 # Version: 7.1
 # Contact: Marcus Schaefer <sax@suse.de>, 2002
@@ -130,6 +130,32 @@
   Identifier   "Modes[0]"
   Modeline     "1600x1200" 178.95 1600 1712 1888 2176 1200 1201 1204 1246
   Modeline     "1600x1200" 208.74 1600 1720 1896 2192 1200 1201 1204 1253
+  Modeline     "1600x1024" 151.68 1600 1704 1880 2160 1024 1025 1028 1064
+  Modeline     "1600x1024" 176.95 1600 1712 1888 2176 1024 1025 1028 1070
+  Modeline     "1600x1000" 147.02 1600 1704 1872 2144 1000 1001 1004 1039
+  Modeline     "1600x1000" 172.82 1600 1712 1888 2176 1000 1001 1004 1045
+  Modeline     "1400x1050" 135.37 1400 1488 1640 1880 1050 1051 1054 1091
+  Modeline     "1400x1050" 158.07 1400 1496 1648 1896 1050 1051 1054 1097
+  Modeline     "1280x1024" 121.35 1280 1368 1504 1728 1024 1025 1028 1064
+  Modeline     "1280x1024" 141.82 1280 1376 1512 1744 1024 1025 1028 1070
+  Modeline     "1440x900" 118.48 1440 1528 1680 1920 900 901 904 935
+  Modeline     "1440x900" 138.31 1440 1536 1688 1936 900 901 904 940
+  Modeline     "1280x960" 112.65 1280 1360 1496 1712 960 961 964 997
+  Modeline     "1280x960" 131.72 1280 1368 1504 1728 960 961 964 1003
+  Modeline     "1280x800" 93.02 1280 1352 1488 1696 800 801 804 831
+  Modeline     "1280x800" 108.77 1280 1360 1496 1712 800 801 804 836
+  Modeline     "1152x864" 91.04 1152 1224 1344 1536 864 865 868 898
+  Modeline     "1152x864" 106.51 1152 1224 1352 1552 864 865 868 903
+  Modeline     "1280x768" 89.32 1280 1352 1488 1696 768 769 772 798
+  Modeline     "1280x768" 104.48 1280 1360 1496 1712 768 769 772 803
+  Modeline     "1024x768" 71.63 1024 1080 1192 1360 768 769 772 798
+  Modeline     "1024x768" 83.00 1024 1080 1192 1360 768 769 772 803
+  Modeline     "800x600" 42.83 800 840 920 1040 600 601 604 624
+  Modeline     "800x600" 50.32 800 840 928 1056 600 601 604 627
+  Modeline     "768x576" 39.22 768 800 880 992 576 577 580 599
+  Modeline     "768x576" 46.12 768 808 888 1008 576 577 580 602
+  Modeline     "640x480" 26.87 640 664 728 816 480 481 484 499
+  Modeline     "640x480" 31.13 640 664 728 816 480 481 484 502
   Modeline     "1280x1024" 121.35 1280 1368 1504 1728 1024 1025 1028 1064
   Modeline     "1280x960" 120.84 1280 1368 1504 1728 960 961 964 999
   Modeline     "1280x800" 107.21 1280 1360 1496 1712 800 801 804 835
@@ -146,23 +172,23 @@
   DefaultDepth 24
   SubSection "Display"
     Depth      15
-    Modes      "1600x1200" 
+    Modes      "1600x1200" "1600x1024" "1600x1000" "1400x1050" "1280x1024" "144
0x900" "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "800x600" "768x576
" "640x480" 
   EndSubSection
   SubSection "Display"
     Depth      16
-    Modes      "1600x1200" 
+    Modes      "1600x1200" "1600x1024" "1600x1000" "1400x1050" "1280x1024" "144
0x900" "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "800x600" "768x576
" "640x480" 
   EndSubSection
   SubSection "Display"
     Depth      24
-    Modes      "1600x1200" 
+    Modes      "1600x1200" "1600x1024" "1600x1000" "1400x1050" "1280x1024" "144
0x900" "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "800x600" "768x576
" "640x480" 
   EndSubSection
   SubSection "Display"
     Depth      32
-    Modes      "1600x1200" 
+    Modes      "1600x1200" "1600x1024" "1600x1000" "1400x1050" "1280x1024" "144
0x900" "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "800x600" "768x576
" "640x480" 
   EndSubSection
   SubSection "Display"
     Depth      8
-    Modes      "1600x1200" 
+    Modes      "1600x1200" "1600x1024" "1600x1000" "1400x1050" "1280x1024" "144
0x900" "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "800x600" "768x576
" "640x480" 
   EndSubSection
   Device       "Device[0]"
   Identifier   "Screen[0]"