I've found this topic when I had the same problem :)
To run tests on 1.2 about text styling, I've only file in the categories Shout-Styling and Shout-Parsing and I had to add a method to PluggableTextMorph :

stylerStyled: styledCopyOfText���
��� textMorph contents runs: styledCopyOfText runs .���
��� "textMorph paragraph recomposeFrom: 1 to: textMorph contents size delta: 0."
���
��� "caused chars to appear in wrong order esp. in demo mode.
��� remove this line when sure it is fixed"���
���
��� textMorph updateFromParagraph.���
��� selectionInterval ��� ���
��� ��� ��� ifNotNil:[
��� ��� ��� ��� textMorph editor
��� ��� ��� ��� ��� selectInvisiblyFrom: selectionInterval first to: selectionInterval last;
��� ��� ��� ��� ��� storeSelectionInParagraph;
��� ��� ��� ��� ��� setEmphasisHere].���
��� "textMorph editor blinkParen."���
��� self scrollSelectionIntoView

With that, i've color in my PluggableTextMorph, but I think it's not the proper way to do it :)