[Mediawiki-l] how to generate a unique page title?

Hi

I'm using the CreateBox extenstion: http://www.mediawiki.org/wiki/Extension:CreateBox

I want the title of each new page created via this extension to consist of 'User/xxxx', where the user substitutes 'User' for their own username, and 'xxxx' is anything unique. I've tried using the following code for the default field text:

User/{{CURRENTTIMESTAMP}}

http://www.chainsofreason.org/wiki/Create_a_new_chain

I used this variable to save the user having to add something unique, given that the timestamp includes seconds and therefore should never be the same on each use. However, the timestamp does not actually change after the user returns to the same page to create another new page - presumably something to do with caching.

Can anyone think of any other way of automatically something after 'Username/' that will always be unique - it doesn't matter what it is.

Thanks in advance for any help.

Derrick