Problem seems to be reported here and there, but I can not found what I really need to fix this during the morning:
... nope, nothing. I found this:
This wordpress plugin is for show custom external rss feed in category page.
For example if you want a category page list rss feed from another site category page, this is for you.
It is my first wordpress plugin (ok, maybe not exactly the very first hello world like ;)
It use simplepie because I like it. (it is included in package and license is almost compatible)
From an idea of: IM Evolution a SEO/SEM Company