restrict username during registration

[clearchannel]

I have this hack installed on my 3.07 board. It restricts the use of special characters in usernames during registration.

I have searched high and low for something similiar for 3.50. Does any know if this is possible in 3.50?

I compared the register.php files for both 3.07 and 3.50 and can not figure out how to accomplish this.

Thanks in advance

[clearchannel]

Granted, I do have the knowledge to accomplish this task, for that I apologize. I would think it was doable in 3.50.

Thank you in advance