diff --git a/README.md b/README.md
index d50f223..e554cb3 100644
--- a/README.md
+++ b/README.md
@@ -25,3 +25,20 @@ Translations
 
 You can translate this addon by translating the strings in the `lang/C/messages.po` file and copy the resulting `messages.po` to the `lang/LNG_CODE` directory of your language..
 To generate the needed `strings.php` file for your language, use the tools [Friendica supplies](https://git.friendi.ca/friendica/friendica/src/branch/develop/doc/translations.md).
+
+Custom Themes
+-------------
+
+If your theme does supply an alternative registration form, you need to supply a modified version of the form to the addon or the addons default template will be used.
+Your theme specific template needs to be placed in
+
+    /addon/matchcaptcha/templates/theme/THEME_NAME/register.tpl
+
+and has to contain the following new fields
+
+
+    <h4>{{$captchaTitle}}</h4>
+    <p>{{$captchaDescription}}</p>
+    {{include file="field_input.tpl" field=$mathcaptcha}}
+
+at the correct position of the form.