Changing Admin Password with Sysprep

I'm using sysprep to prepare a windows xp sp2 image for deployment with
ghost. I'm also using winbom to install additional drivers and software.
Since winbom auto logs on as administrator, i have set the admin password to
blank. When the mini setup for sysprep attempts to change the admin
password, it tells me that it failed to change the password. I click ok on
the error, it it appears to give me a brief chance to change the password but
moves on before i can do so. Once sysprep is done the admin password is
still blank.