automated install stop at a customize user interface

[kin boster <kinboster@gmail.com>]

hi all:
       I base lenny installer customize a user interface : my_test, gave it menu-item number 1500: after load installer components and before network configure
       It can run normally except automated install.
       When i run automated install, the installer  stop at my_test interface. But this interface's answer had written in preseed file, 
       why installer can't automated continue?   

       any idea?

       best regards
       Boster