Summing And Grouping Numeric Fields

Hello again

How do I sum up and group numeric values into one output column in SSIS?

I have data that looks like this:

Refno date credit amount

11675 1987-04-23 7.03 13501.27


and I want to add the credit and amount columns together and output them as one column, In T-SQL, i'd do this:

SELECT Refno, SUM(Credit + Amount)

FROM Transfer

GROUP BY Refno, Date

I could add this SQL into my SSIS package easily enough but I wan't to learn how to do it the SSIS way