Is there a Samaccountname User Logon Generation restricted characters whitespace character?

We are using the User Logon Generation policy.

It works great. I have it set to department acronym first initial last name.

So if John Jones gets hired at the department of business he gets DOBJjones for a samaccountname. 

The question I have is regarding users with a space in their name.

For instance:

John Jones Jr

He will get DOBJJones Jr for a samacountname. 

Under advanced in the user logon generation policy I see Restricted Characters. I have tried adding a literal space, like actually hitting the space bar, and saving. That didn't do the trick. Is there an escape character or something that represents whitespace in this context?

Generates user logon name (pre-Windows 2000) based on directory data such as user properties

This policy generates a user logon name (pre-Windows 2000) for a user account being created. You can configure it to:
- Add a uniqueness number to the generated logon name
- Apply multiple rules to generate a logon name
- Allow a logon name to be specified manually during the user creation process

By combining these options, you can ensure the uniqueness of the user logon name (pre-Windows 2000), which is a schema requirement in Active Directory.