Here is a link for Phil Brammer article on using the checksum component for ssis.

http://www.ssistalk.com/2007/03/09/ssis-using-a-checksum-to-determine-if-a-row-has-changed/

When I implemented the checksum, I did all of it from T-SQL. Allow me to explain -

1. I have a base and a staging table identical in schema. Data from my import is loaded into my staging table. On the staging table I have added an additional column (checksum value) that is a computed column contain a checksum over all of the columns of the staging table, with the exception of a few columns. As data is loaded into staging table, checksum value is computed on the fly.

2. Once data has been loaded into the staging table, I perform a comparison between the staging table and base table.

a. Delete - delete from base table where business key not exist in staging table.

b. Update - create a checksum value over the columns of base table and compare that checksum value and business key against the checksum value and the business key of the staging table. If not equal update, else ignore.

c. Insert - where business key not exist in base table.

If you like I could create a mockup of the syntax for you if that would make more sense. I am more of a visual person my self so sometimes this helps. A picture is worth a thousand words.