1. Use the OLEDB source component. In the source editor, choose the 'Data Access Mode' as SQL Command.
2. In SQL Command Text, provide the procedure to be executed. Eg : Exec USP_MyCalc ?, ?
3. Use the parameters button in order to pass the relevant values from SSIS variables. Map them to the name of the params in procedures. (@param1 = @User:choice1)
4. You might not be able to view the columns( in the source editor) because the stored procedures do not provide the metadata.
5. Now you can map the output data of the source to a transformation component or a destination as you desire.