I think you are posting the same question as you did here: http://www.mojoportal.com/Forums/Thread.aspx?thread=3619&mid=34&pageid=5&ItemID=4.
Please do not post your question multiple times as it doesn't help get it answered. I will try to answer your question but I think we are having a communication problem because of our different native languages.
If I have read your question correctly, you want to retrieve blog posts via the Feed Manager and you want the date for each post included in the feed. If that is not correct, please say so.
To do this, all you need to do is the the url of the blog's RSS feed to the feed manager. The date shows up automatically when doing this, in fact, I don't think you can remove the date from the posts using the feed manager.
HTH,
Joe