set bleed top to 2inch--indesign cs4

Hi All,
I am using below syntax for exporting PDF with my own preset. I want to change the value of bleed top to 2 inch. Then I want to export the PDF.
Please suggest how can I do that.


tell application "Adobe InDesign CS4"
tell PDF export preferences
set bleed top to "2in"
end tell
tell document 1
export format PDF type to "Macintosh:Test.pdf" using myPresetName without showing options
end tell
end tell

Please let me know where I am doing mistake.

Regards,
Poo

Can any one help me due to this issue I am not able to release my developed module.:frowning:

Regards,
Poo