Hi. I believe the answer (with Freehand 10 at least) is to:
1. Convert the large letters into outlines. Select the stroke and fill you
want for the outline letter forms.
You may have to ungroup them.
2. Then select the text box with the smaller size lettering and using the
menu, Text > Flow Inside Path
command, select the first letter outline you want to fill. The text will place
itself inside the letter.
You can modify how far from the edge the inside lettering goes using the
Object Inspector.
3. Following this, flow the text into the next letter outline form by dragging
the little box filled with
the solid circle at the bottom of the outline path to the next outline letter
form. As you drag,
the box will not move, instead an arrow will follow your cursor and when you
drag it to the next
path to fill, release the arrow and the letter form will fill. Repeat #3 until
finished.

E Morris