Wpomatic WP-o-Matic

Hello. First of all, what a great plugin! Thanks for such amazing stuff. I am using wp-o-matic plugin. version 1.0RC4-6. The simplepie test was ok and the server passed successfully each test. I created campaigns with ease, fetching worked fine and created new posts as expected. I am checking feeds updates once a day, automatically or with manual fetch. I know that new post were added to the original feed, but the plugin does not detect any new post! The log show that campaigns are processed with no errors but with “no new posts”. First I checked the how the source of rss feed which is rss 2.0 version, with pubDate info as “Thu, 04 Sep 2008 22:01:22 +0200”. Then I tried to reset the campaign and fetch it again... No new post discovered either... If I remove all the created posts and then fetch the whole campaign again, then all the posts are successfully imported (even the new ones previously not detected). The problem is that I do not want to do this process each time, since tagging the new content takes time. I have experienced this issue both in the production server and the local testing computer. Does not seems to be a server configuration problem. Please help me solve this. Best regards