Custom size on Mac OS 10.2.8

[Horky Chen]

Dear all,
I wrote a GDI printer driver, and I found a big problem on Mac OS X.2, I have post my question in Printing mailing list, but there is no any response. So I ask you for your kindly help.
On Mac OS 10.2.8, I use CustomPageSize in PPD file to describe my custom sizes. But when print the landscape format data with some custom size, preview is correct, but the printer output is Portrait, and top of the paper is blank.

Followings are my testing result:
  4.17inx8.64in  OK
    4.17inx8.66in  NG
  4.17inx8.68in  OK
  5inx8in        OK
    7.87inx9.84in  NG

Here I list the definition for custom size in my ppd:
*MaxMediaWidth: "612.00"
*MaxMediaHeight: "1008.00"
*HWMargins: 15 15 15 15
*CustomPageSize True: "pop pop pop <</PageSize[5 -2 roll]/ImagingBBox null>>setpagedevice"
*ParamCustomPageSize Width: 1 points 283.00 612.00
*ParamCustomPageSize Height: 2 points 595.00 1008.00
*ParamCustomPageSize WidthOffset: 3 points 0 0
*ParamCustomPageSize HeightOffset: 4 points 0 0
*ParamCustomPageSize Orientation: 5 int 0 0
*RequiresPageRegion All: True

Anyone come across this before, or have any ideas how to deal with the problem?

Thanks in advance!