[kh99]

There are two ways you can do this: you can copy the code from the template block_html (under the Block Templates group), and to your custom template. Copy everything above the line {vb:raw content} to the top of your custom template (before any of your code), and everything after that line to the end of your template. Then when you create a "Custom HTML/PHP" forum block, replace "block_html" (in the Template to Use field) with your template name.

The other way, which you'll have to use if your template has variables that you want to set or if you don't want to change your template, is to choose content type "PHP" (using the radio button), and then include code to render your template and return the result, like:

$template = vB_Template::create("my_custom_template");
$my_output = $template->render();
return $my_output;