url are retrieved both by title and alias

Hi,

I found that google retrieve all my articles by two sides, so he tell me that my titles and descriptions are in double.

One url by the title:
url of my site/news/hardware/memoire-ddr2-kingston-hyperx-pc6400-:-le-cas-3,-perf-ou-pas-perf?-20070627904.html

And one url by the alias set on the article:
url of my site/news/hardware/memoire-ddr2-kingston-hyperx-pc6400--le-cas-3-perf-ou-pas-perf-20070627904.html

The actual settings of this article are:

Title: Mémoire DDR2 Kingston HyperX PC6400 : le cas 3, perf ou pas perf?
Alias: memoire-ddr2-kingston-hyperx-pc6400--le-cas-3-perf-ou-pas-perf

And I must say that my "Use title alias" is set to YES 

So shouldn't this article only see by one side ? If an alias is set, so this must be only accessible by an url with the alias, no ?

I remember that I haven't got that with joomla 1.0.x

And I'm wondering if this is normal that I can access to this article even by this url ?
url of my site/news/hardware/perf-20070627904.html

The only way to get the 404 is to change the unique ID at the end of the URL, but by this way we can often reach another article or a category.

Thanks by advance for the explanations

When you use "unique URL" feature then the article is accessed by the ID passed in the URL. It doesn't matter what you have before that, the names are merely for SEO purposes.

So you should be careful not to change such features AFTER you have been indexed by Google or, if you do, to define redirects from old URLs to new ones.