dialog programming

hi,

my scenerio is

Based on sales order No which i give in selection screen(created in se51)it will go to next screen and details of that particular sales order will be displayed.

my code is:

call screen 9000.(selection-screen).

in pai module:

case sy-ucomm.

when 'GEN'.

leave to list-processing.

here i hav written

select query for details of particular sales order no .

wen calling next screen details not coming,,,,please help if someone have idea,.