I know that keywords should appear on top left. But I don't understand how a search engine see what is on top left. A text which is shown inside a code in the first line as first characters inside this line is considered to be on top left? Just simple as that? And to change a position you just use css absolute attribute to change it?
That does work and is being used in my redesign. You can view your site as the spiders see it here: http://www.webconfs.com/search-engine-spider-simulator.php You can code to talk to the spiders but make the text/images appear appropriately for human visitors.
I try to put my main keywords as soon in the code as possible. I wouldn't just worry about screen position. Consider what the spiders will read first as they crawl through the page's code.