Currently it’s not possible to get either 1004 or 1012 MTs as output from an RS2 receiver.
Although the Ublox F9P chip does actually support these legacy MTs, Emlid have only enabled MSM4 message types as correction output via ReachView
In other threads I have politely requested that the Emlid development team consider supporting classic/legacy MTs including 1004/1012 but there is no firm plan or date of this is to be achievable.
So short answer is you only have MSM4 output to work with I’m afraid. Some receivers are happy with this, ComNav, Spectra and some are not (various Trimble and Topcon ag receivers). Whether JD Starfire 6000’s will accept MSM4 you can only tell by asking JD or trying it for yourself.