Custom Permalink structure break the slider

Hi.

If I select this permalink setting
/%category%/%postname%/
The featured images don’t show in the slider. The same pages work fine in the Services widget though.

The slider picture pages are under a slider parent page as done in the tutorial (they also work without that).
When permalink is set back to plain, it works ok again with no further change.

Permalink settings are capital from the SEO point of view. Your managing of sections by pages is why I choose your theme between others (it’s more seo friendly). But that feature would kill all the effort.

¿Can you point a way to solve this? I don’t mind modifiying entries in the database for the slider pages or images, or editing the php files.

Thank you for your support.