First I took a look at CM's apns-conf.xml in Notepad+.
Then I found & edited the apn 'Boost Mobile CdmaNai' (as that is the one that applies to my device) to read as follows
I then amended CM's build prop with 4 lines
When I rebooted all was well with MMS & carrier label
Then I found & edited the apn 'Boost Mobile CdmaNai' (as that is the one that applies to my device) to read as follows
I then amended CM's build prop with 4 lines
When I rebooted all was well with MMS & carrier label