Not in that interface, but you can use an external POP client like MS Outlook or Mozilla Thunderbird.

POP Server:* mail.domain.com
User:* email@domain.com
Pass:* email pass

same info for incoming and outgoing, no SSL.

This is so simple to do. I just added a new Webmail. I didn't like Horde, and Squirrel just seems to plain.

I looked and found Roundcube. This looks real nice and so far its' running smooth..
Heres the steps I took to install it.
Logged into my WHM, Then set a Master database password (remember this)

Went here.

Logged into SSH with putty and followed that tutorial. To install RoundCube.
Then found the email wouldn't send.
I found and made this change.

Look in /usr/local/cpanel/base/roundcube/skins/default/templates/compose.html at about line 31 and change the action from:
to "index.php"
This change seems to allow the email to be sent.

Once that was done, Roundcube comes up with Horde and Squirrel mail.