If you want to allow variables in your setting text, you need to use a plugin to eval() the text before using it in a template. For example:
Code:
eval('$my_setting = "' . $vbulletin->options[my_option] . '";');
Then use $my_setting in your template. If you do this, you should be aware that anyone who has access to the settings can execute any php code they want.
Using eval will allow you to use variables in your text. If you also want to use template tags (for example, <if condition=...), then you would need to use the template compiler.