samba - Jul 2010 - smbpasswd doesn't accept -'s in username?

Hello

Since Lighttpd sets /var/www to www-data, I ran this:

# grep -i "www-data" /etc/passwd
www-data:x:33:33:www-data:/var/www:/bin/sh

# smbpasswd -a "www-data"
New SMB password:
Retype new SMB password:
Unable to modify TDB passwd: NT_STATUS_UNSUCCESSFUL!
Failed to add entry for user www-data.

Can you confirm that Samba doesn't allow dashes in usernames? Is there
a work-around?

Thank you.