Search Serial-Number attribute of Computer object in AD

Hi,

I want to search Serial-Number attribute of Computer objects in AD. i donot know whether DSget/DSquery will do this job but i am trying with ADFind & using the below syntax. I have added manually one Computer's Serial-Number field with ADSIEDIT & trying to search with ADFind but getting no records. Kindly help me to get this info. later on i have to import this field from a csv file.

ADFIND -b "ou=users,dc=MyDC,dc=com" -f "(&(objectclass=computer)(serialNumber=*))"

But it's showing 0 Records returned.

Dhiraj