Hi Juan,

Sorry it took so long to get to this.  I meant to send a reply right away, but it must have slipped my mind and I apologize for that.

The Trackback feature in the blog module is separate from the Trackback and Pingback implementation provided in metaPost.  The configuration you have included above is only useful for when you are creating posts online.  If you want to enable auto Trackback and Pingback with metaPost, then you have to set the Pings dropdown to Allow.  This dropdown is visible in a collapsable region at the bottom of WLW when you are creating a blog post.  You will need to click on double arrows at the bottom right part of the WLW screen in order to see this region. 

If this doesn't make sense, feel free to post here in the forums or give me a call or chat through Skype (dworthley).

Thanks!

Don