How do I achieve scolling effect with dynamically updated messages?

Hi all, after reading through 4 Flash books, I still can't quite figure out how to do this:
a simple Flash movie that looks like a table of rows and columns, whose data for each rows and columns are dynamically updated by loadVar from a PHP script...but how to 1) use a timer to pull data from PHP say every 5 seconds (use Timer class I think); and 2) if there is new data (as indicated by a time stamp for that new data), display that data as the first row, and scroll down the old (already existing) rows ... so all the existing data will persist.

I don't quite understand the mechanics behind this: does Flash internally "save" all the exiting rows of data, and only displays the new row(s) as they become available ? or each time it pulls data from PHP, it displays all available rows of data all over again?

By the way is there a sample FLA file show how a "table" like form be set up in Flash?

thanks a lot in advance,

pt.