Editor Compatibility, Dreamweaver MX

Has anybody worked with Dreamweaver MX to do CSS stuff on it. I am using that program right now, and I have the annoying symptom of something not looking right on Dreamweaver but looking right on my browser (IE 6.1). Perhaps I am doing something wrong.

I made a table (which is like my main window) and made it align="center". I tried to use CSS to make it centered in the browswer, but I couldn't figure out how. Then I placed a <div> tag in one of the cells with relative positioning, which I was hoping would be relative to the edge of the table. Well in the browser it works, but in Dreamweaver it doesn't.

Am I doing it wrong? Is there a better way? Has anybody else experienced this? Is there a work around?

I'll take an answer to any of these. Thanks