CC's second level support was unable to get my new Samsung Galaxy S4 Mini GT-I9190 (4.2.2) working with the browser, and send/receive text messages. I developed the following APN setup which works for:
1. Internet/Browser access
2. Text messaging to/from -- with pictures.
3. Text message emailing to/from -- with pictures.

All settings blank/not set/default except the following:
Name: ConsumerCellular
APN: att.mvno
Multimedia Message Proxy:
Multimedia Message Port: 80
MMC: 310
MNC: 410
Be sure to SAVE
NOTE: Mobile Data must be on for pictures to send/receive via MMS.
Also be sure Data and Messaging are enabled on your CC account for this phone.