Ok I was able to “Replace” the Expert Text by a full custom field.
1) I’ve hook a custom field (code field) at wpsp_before_content
2) I’ve name the div of the content if the field the same name as the div card style use to display Exerpt text:
<div class="wp-show-posts-entry-summary"><p>my custom content</p></div>
Then, I can display a full text different (from a custom field) into the wp-show-posts-entry-summary
Such a pain, but I’m so happy now =)