User create fails while generating a username with a whitespace

When a user signs up for our community website it is stored in our OpenLDAP server. The user needs to fill in his first and last name and i have disabled the custom usernames and set a username template like this: "%f.%l".

But when a user with a middle name wants to join for example: "Henk de Boer" and the user fills in "de Boer" as last name or "Henk de" as first name, the validation email will be send out but when the user try to validate the account has not been created and the username and password has not been send out to the users email address.

Also while you are in this process and the user validates his email correctly, it will be redirected to the login page but there is no message that the credentials are mailed out to the email address of the specific user.

I created a quick fix like this in ldapprov.module line #1555

$first_name = str_replace(' ','.',$first_name);    
$last_name = str_replace(' ','.',$last_name);