X-Cart forums - X-cart 5 - No custom payment module after module installation

Hello,

I'm just trying to develop a new payment plugin for a PSP, but after following the two "tut's" for creating a payment plugin I'm stuck...

The two tut's I followed:
http://kb.x-cart.com/display/XDD/Creating+payment+method
http://kb.x-cart.com/display/XDD/Creating+settings+page+for+payment+method

Before somebody is telling me that I'm able to download both modules, I already did. I'm, like my custom module, able to find in the Payment settings but not able to install.

With "install" I mean that I'm able to click on "add" in the select list just like the tut is saying:
http://kb.x-cart.com/download/attachments/8225448/add_demo_payment.png?version=1&modificationDate=14 3756...ts=drop-shadow

But I've also a button "install".
When I click on the "install" button, I'm redirected to the front-end of the shop, when I click on "add", the system is telling me that the module is added, but it doesn't show up under "Online methods" of the "Payment settings".

Environment info (this is my development machine)
Core version:
5.2.13

Installation directory:
/var/www/plugins/xcart/5213

PHP:
5.6.17-0+deb8u1details

MySQL server:
5.5.47-0+deb8u1 (InnoDB engine support enabled)

Web server:
Apache/2.4.10 (Debian)

Operating system:
Linux

XML parser:
found

GDLib:
found (2.1.1)

Translation driver:
Database

Curl version:
7.38.0