Hi,
default value works on registration form, but you need to have this field available for registration page.

To solve your problem you can build a very simple plugin based on our skeleton plugin, follow these steps:
- Download, Install and enable skeleton plugin, you will find this at the end of docs page at http://docs.easy-profile.com/index.php/article/triggers
- Open file /plugins/jsn/skeleton/skeleton.php
- Remove samples functions like: triggerFieldAvatarUpdate, triggerProfileUpdate
- Write function to do this like:

public function triggerProfileUpdate($user,&$data,$changed,$isNew)

{

	if( $isNew ) // only when you create user

	{

		$data['aliasOfField']='default value';

	}

}

Skeleton plugin is very useful, you can use it to make operations (for example sum between fields), get/set data from/to DB table, send emails with custom fields, generate random code for some field, etc....

Docs at http://docs.easy-profile.com/index.php/article/triggers