Email addresses with spaces

[Clayton Scott Kern <ckern1@xxxxxxxxxxxxxx>]

I'm not sure if this is the right place to address this.

I use fetchmail -> sendmail -> procmail -> mutt.

I have problem with emails that have spaces in the user name.
For example  joe doe@xxxxxxxxxxx

Mutt doesn't display them in the index page.  For now, I've been editing
the mbox file and putting an underline in the email address.

I've looked through the manual and if there's a setting to handle this,
I'mm missing it.  Or should I be handling this with either procmail or
sendmail?

I'm using mutt version 1.4.2.3 on a FreeBSD 6.3 system.

Thank you in advance.

Scott