An alternative way to make a MAT pose. Set up the materials in your figure as desired, and save the figure to the Figures palette. Install the free "CR2Builder". Use a text editor to make a template file as below, and save it to disk as "MAT Template.pz2".

{
version
    {
    number 3
    }
figure
    {
    #material blocks go below this line.

    }
}

Open CR2Builder. In the Left TV, open your figure's cr2, in the Right TV, open the template pz2. Scroll down to the bottom of the figure's cr2, expand the "figure" section. Scroll down to the bottom of the figure section, you will see the materials. Click on the first line that starts with the word "material"  to select it, then hold down the Shift key, and whilst still holding it down, click on the last line that starts with "material", after a few seconds all the materials should be highlighted. Click and hold down inside the highlighted area, and drag it across to the Right TV, and drop it on the lane that says "#material blocks go below this line".

Save the MAT pose in the Right TV to a Pose folder with the desired name and a ".pz2" file extension.