SSIS - Passing a date parameter to a SQL Query question again....

I need to pass a date string to my sqlcommand inside of my "datareader source".  I read some of the questions about setting expression variables but I can't seem to figure out how to do it.  I pasted the query below.  The table name contains a date in it so I need to pass that date as a string into my sqlcommand at runtime.  Do I create a variable with the entire SQL command in it or can I just create a single variable that holds the date and just reference that in my datasource reader sqlcommand property?  Can someone assist me with the syntax for creating the expression?

SELECT
     pages_20101006.`date` AS full_date,
     pages_20101006.`cat` AS category_no,
FROM
     pages_20101006

Thanks very much,

Chris