ForEachLoop Container And Variables

Hi Guys



I am trying to do the following and am quite new to SSIS.



I have to select a dataset from a database on server A, check if it exists on server B and perform an Update or Insert dependant on the existence.



I have created a SQL task to do the Select from server A with the results set passed to a variable of Vendors. I have added a ForEach Loop container with an enumerator of Foreach ADO Enumerator and the source variable is set to Vendors.



I have created 2 variables in the Foreach Loop called Code and Supplier - both as strings - as there are 2 fields from the initial Select that need to be passed to the final Update/ Insert.



I have then created another SQL task insert the Foreach which will perform the Update/Insert.



obviously when I run it at the moment it performs the Update/ Insert but just adds the rows with both Code and Supplier as NULL.



having looked at a couple of examples in books I have i know i need to add something in the Expressions of the Update/Insert SQL task but it is here i get a bit lost.



Which of the properties from the drop down do i need to use to map the variables against?



Any help would be massively appreciated asI am tearing my hair out!



Thanks



Scott