SSIS Sort and Script To Remove Duplicates

Hello!

I have developed a Package that will read from an Excel file, and then Sort the data on CaseID and then I use a Script Component to Remove Duplicates and send Unique Values to one DB Table and Duplicates to another. When I Sort the Data I get the following with my Duplicate Rows. What I would like to ask is how can I get the NULLS last in the Sort and my Row with Data First in the Sort? Everything is working but it is putting the Rows containing NULLS in my Valid Data Table instead of my Duplicate table.  Thanks! Mike

CaseID  Current                Tax Service         Tax Service1       Tax Service2       Tax Service3       Transmittal         Included on                Address               City        County State     Zip Code              Acquisition          AM NAID             AM Name           AM Assigned

271-936124         NULL     NULL     NULL     NULL     NULL     NULL     NULL     NULL     NULL     NULL     NULL     NULL     NULL                NULL     NULL     NULL

271-936124         2-Appraisal Complete    Completed         07/06/2011         07/15/2011         07/20/2011         08/05/2011         Yes                401 ROSE DRIVE                FARIBAULT         RICE       MN        55021-0000         06/29/2011         BSTSST9432        BEST ASSETS INC         07/05/2011

Mike Kiser