Sounds like you are trying to take M1/M2 to M2P4 or V1/V2 to V2P4.

Do it this way:
Spawn your face morph, name it a real name, not shape 1.
Save the character file as a new character.
Open this new CR2 in MM4 (or CR2Edit) (Mac = MC) and open the CR2 where you want it beside it.

Find the morph, right click and Copy. Save your target CR2 and there it is.

Not only can you get V1/V2 morphs to V2P4, but you can get V1/V2 morphs to the Mil Kids the same way.

If you are going to do much of this, you might consider MORdonor poses as an alternate method.
The same face pose file could be used on a base Vic, V2P4, or any of the four Mil Kids - if practice matches theory -
as long as all have the same targetGeom host.
This is not to say that the faces will look good on the Kids. The same holds for body morphs on the Kids, they will transfer, the results they produce depend.
V2P4 is a wash for anything but head morphs.