I have no solutions yet.
I explain again with another precisions:
I use Custom Post Type to list projects.
I use "Custom Post Type UI" plugin to register the custom post type.
Permalinks are set like this : /archives/%post_id%
I set in wordpress a "Portfolio" page as the front page and another page for the Blog.
So the Portfolio page is the front_page and the Blog page is the home. (I had confirmed this by checking with
is_front_page(); conditional tags.
So my template loop is fine, I test it on another page and it works fine but it does not work on the front page for the reason I exposed on first post.
The "older entries" link correctly displays on my Portfolio front page but links to nothing :
The reason is that It should be
http://mywebsite/my_front_page_slug/page/2 to work properly, but the slug of the front_page does not appear.
So to solve this issue, I need a way to put the slug of the static front_page (here "portfolio") to the link generated by
next_posts_link(); template tag only on this specific page.
Hope that makes sense.