TYPO3-6.2 Extbase custom content type -> invalid value - typo3

Question

I made an extbase Extension for custom content elements. Since this is my first extension I started with a simple "hello_world_ce". This are my files:
ext_tables.php
<?php
$TCA['tt_content']['types']['hello_world_ce']['showitem'] = '--palette--;LLL:EXT:hello_world/Resources/Private/Language/locallang_mod.xlf:content_element.hello_world.general;general, --palette--;LLL:EXT:hello_world/Resources/Private/Language/locallang_mod.xlf:content_element.hello_world.header;header';
ext_localconf.php
<?php
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addPageTSConfig('<INCLUDE_TYPOSCRIPT: source="FILE:EXT:'.$_EXTKEY.'/Configuration/TypoScript/ModWizards.ts">');
ModWizards.ts
mod.wizards {
newContentElement {
wizardItems {
hello_world {
header = LLL:EXT:hello_world/Resources/Private/Language/locallang_mod.xlf:content_tab_header
elements {
hello_world_ce {
icon = gfx/c_wiz/regular_header.gif
title = LLL:EXT:hello_world/Resources/Private/Language/locallang_mod.xlf:content_element.hello_world
description = LLL:EXT:hello_world/Resources/Private/Language/locallang_mod.xlf:content_element.hello_world.description
tt_content_defValues {
CType = hello_world_ce
}
}
}
}
show = *
}
}
}
In the TYPO3 Backend I see my content element and can add it to a page but the dropdown menu for the content type says INVALID VALUE ("hello_world_ce")
What am I missing?
EDIT: I found the missing part. I needed to add my content type to the CType array
ext_tables.php
$backupCTypeItems = $GLOBALS['TCA']['tt_content']['columns']['CType']['config']['items'];
$GLOBALS['TCA']['tt_content']['columns']['CType']['config']['items'] = array(
array(
'LLL:EXT:'.$_EXTKEY.'/Resources/Private/Language/locallang_mod.xlf:content_tab_header',
'--div--'
),
array(
'LLL:EXT:'.$_EXTKEY.'/Resources/Private/Language/locallang_mod.xlf:content_element.hello_world',
'hello_world_ce',
'i/tt_content_header.gif'
)
);
foreach($backupCTypeItems as $key => $value){
$GLOBALS['TCA']['tt_content']['columns']['CType']['config']['items'][] = $value;
}

Answer 1

The question was edited, but I think there is a better way to achieve the solution.
Only to be clear about the problem:
The content element hello_world_ce was not added to the "types" dropdown by adding a new content element.
The hint in the question is correct it was not defined for the CType field.
But instead of manipulating the array you could use a core function:
// Adds the content element to the "Type" dropdown
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addPlugin(
array(
'LLL:EXT:your_extension_key/Resources/Private/Language/locallang_mod.xlf:content_element.hello_world',
'hello_world_ce',
'i/tt_content_header.gif'
),
'CType',
'your_extension_key'
);
Here is a very good example of how to add your own content element in the version TYPO3 7.6.
Note: This function is accessible in TYPO3 6.2 as well.