[Plugin: Manageable] change page Author

First, thanx ys a grate plugin. And work perfect with post but I′m trying to change the author of all the pages on my site usign your Manageable. On the WP are two users one admin and other xxx, those pages was created and edited by xxx and that was on the RSS and the page it show the creator is xxx, for some reasons the owner of the site what that all pages say that admin is the creator.
I′m login with the xxx user and try to change it with the Manageable Plugin but it on the author selector doesn′t show the admin! it is ok?. By the way, the xxx user have an administrator role.

https://www.ads-software.com/extend/plugins/manageable/