Custom Page Templates Reloaded plugin

Hi Pals!

I’d like to use this plugin but:

1. If i used it on an exist page: see the options in the page attributes, and i can edit the “other” template. But if i published the page, the options is hide from the page attributes panel, and what i wrote in the template edit, that works to one refresh on the site.
Otherwise the page is in the original theme.

2. If i used it on a new page: see the options in the page attributes, and i can edit the “other” template. But if i published the page, the options is hide from the page attributes panel, and what i wrote in the template edit, that did not work and said error 404. Otherwise the page is in the original theme.

If i could not use this plugin correct, then how? :S

Thx Samy

https://www.ads-software.com/extend/plugins/custom-page-templates-reloaded/