Custom login module doesn't work in SP9

Hi,

I have one custom login module which works fine in SP2, but when I deployed it to SP9 using the instructions found in:

http://help.sap.com/saphelp_nw04/helpdata/en/46/3ce9402f3f8031e10000000a1550b0/frameset.htm

It doesn't work, throwing some java.lang.NoClassDefFoundError: com/sap/security/api/UMException

exception right at the login screen when user try to login portal.

I wonder if it is because com.sap.security.api can't be found? But I did add com.sap.security.api.jar to the project, and confirmed it is the same version (11/11/2004) as in /usr/sap/PQ1/JC00/j2ee/cluster/server0/bin/ext/com.sap.security.api.sda/com.sap.security.api.jar

Can anyone shed some light? Thanks a lot!

Sean