Send a serial number to each new members?

[ThomasR]

Hi!

I'm currently setting up a forum for one of our product which will be available as a public beta. To activate this public beta, a serial will be need.
Then, I would like to find a way to automatically send a unique serial number to each new members in the welcome email (or in another email, it's not a problem) and then, having this serial number display somewhere if the users is looking again for it.

Do you know if a module or plugin can do that? I'm currently looking all the download plugins, but none of them seems to have such feature.
Any idea?

Thanks!