There are a few settings in the NullDC cfg file that need changed.
This is just from memory, so it's not very complete info, but.....
One sets the default gdi to whatever game selected in MALA
The other makes Demul automatically load the default gdi when started.
(after enabling this, Demul will not work when launched by itself, but will when launched through MALA)
I seem to remember default being spelled wrong in the cfg file and you're supposed to leave it that way.
There are step by step instructions on here somewhere.
You just need to search.