[Verizon Galaxy Note 3 Android Development] Gunthermic:
I didn't find how to do this, but rather..

[MENTION=3449508]JoelZ9614[/MENTION] over here Fix for MMS in Hangouts - Verizon

I am just sharing with all you peeps.

1. Decompile Hangouts

2. Go to res/xml/apns.xml

Add:

<apn carrier="LTE - VZW Roaming Internet" mcc="204" mnc="04" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Roaming FOTA" mcc="204" mnc="04" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Roaming IMS" mcc="204" mnc="04" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Roaming CBS" mcc="204" mnc="04" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="EHRPD - VZW Roaming Internet" mcc="204" mnc="04" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Roaming FOTA" mcc="204" mnc="04" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Roaming IMS" mcc="204" mnc="04" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Roaming CBS" mcc="204" mnc="04" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="LTE - VZW Test Internet" mcc="246" mnc="81" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Test FOTA" mcc="246" mnc="81" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Test IMS" mcc="246" mnc="81" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Test CBS" mcc="246" mnc="81" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Test Internet" mcc="246" mnc="081" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Test FOTA" mcc="246" mnc="081" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Test IMS" mcc="246" mnc="081" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - VZW Test CBS" mcc="246" mnc="081" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="EHRPD - VZW Test Internet" mcc="246" mnc="81" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Test FOTA" mcc="246" mnc="81" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Test IMS" mcc="246" mnc="81" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Test CBS" mcc="246" mnc="81" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Test Internet" mcc="246" mnc="081" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Test FOTA" mcc="246" mnc="081" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Test IMS" mcc="246" mnc="081" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - VZW Test CBS" mcc="246" mnc="081" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="Verizon Internet" mcc="310" mnc="004" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" />
<apn carrier="Verizon FOTA" mcc="310" mnc="004" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" />
<apn carrier="Verizon IMS" mcc="310" mnc="004" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" />
<apn carrier="Verizon CBS" mcc="310" mnc="004" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" />
<apn carrier="Verizon" mcc="310" mnc="006" apn="internet" type="default,mms,dun" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" />
<apn carrier="Verizon Internet" mcc="310" mnc="006" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" />
<apn carrier="Verizon FOTA" mcc="310" mnc="006" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" />
<apn carrier="Verizon IMS" mcc="310" mnc="006" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" />
<apn carrier="Verizon CBS" mcc="310" mnc="006" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" />
<apn carrier="LTE - Verizon Internet" mcc="311" mnc="480" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - Verizon FOTA" mcc="311" mnc="480" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - Verizon IMS" mcc="311" mnc="480" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - Verizon CBS" mcc="311" mnc="480" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="14" />
<apn carrier="LTE - Verizon SUPL" mcc="311" mnc="480" apn="VZW800" type="supl" protocol="IPV4V6" bearer="14" />
<apn carrier="EHRPD - Verizon Internet" mcc="311" mnc="480" apn="VZWINTERNET" type="default,dun" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - Verizon FOTA" mcc="311" mnc="480" apn="VZWADMIN" type="fota" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - Verizon IMS" mcc="311" mnc="480" apn="VZWIMS" type="ims" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - Verizon CBS" mcc="311" mnc="480" apn="VZWAPP" type="cbs,mms" mmsc="http://mms.vtext.com/servlets/mms" protocol="IPV4V6" roaming_protocol="IPV4V6" bearer="13" />
<apn carrier="EHRPD - Verizon SUPL" mcc="311" mnc="480" apn="VZW800" type="supl" protocol="IPV4V6" bearer="13" />

Compile.. and bang you have working MMS in Hangouts for Verizon carrier..

To Fix AT&T.. Nevermind, been told AT&T is functioning...

Also to adjust... MMS mesage size

edit res/xml/mms-config.xml