How to assign user variable value to the Derived Column, in Data Flow Task

Hi:

In the derived column transformation editor, I have a Derived column name called FileGroupID. I would like to pass in a value for this column from a variable that I have set earlier in the scope. Can someone let me know, how to write the expression that does that and where do I specifiy that expression. I am thinking its the expression field in the derived column transformation editor. My main question is how to actually write the expression, what is the syntax to pull the variable value? Thanks.

MA2005

@.[User::YourVariableName]

Actually from the top left side you can expand the variables folder and drag-and-dorp it on the expression field; so you avoid the typing.