You can already do this without creating a new custom field.
1. create a text field for the 8digit-number.
2. set its style attribute to hidden in
the template override from
form.php
or add a class within flexicontent.
3. set its value via php in
form.php
Code:
value="<?php echo microtime();//use custom ?>"
4. include the value into the email sent to user
EDIT:
Sorry, Point3 seems not to work in flexicontent. Its here far more complicated and not accessible as other cck's from Joomla. You have to do it via Javascript for ex.
Code:
<script>
document.getElementById("custom_field77_0").value = new Date().getTime();</script>
But this is dangerous because it could be altered by user. Serverside is needed even here to check uniqueness (and vulnerability if out-of-framework saving).
AT ggppdk: How can we access/differ the form value in form.php to be preset onload?
i see it to be called only prestructured like