Mix the water, soymilk, sugar, salt, molasses and oil in a bowl.
Add the yeast to the soymilk mixture, then add the whole-wheat flour and the vital wheat gluten flour.
Mix by hand or in a stand mixer until just combined. Then add the buckwheat flour and the rye flour.
Knead for 10 minutes on low speed or by hand. Keep about 1/2 to 1 cup of whole-wheat flour on hand to add in case the dough is too sticky. You want a smooth, elastic dough that does not break easily.
Oil a bowl and place the dough in it, turning it around once to ensure it is coated all over with oil.
Set aside in a warm place to rise for an hour to 90 minutes.
Remove the dough from the bowl, punch it down, shape. If you'd like to make it in loaf pans, divide the dough into two halves, tuck the edges under for a smooth top, and place in oiled loaf pans coated with some cornmeal.
If shaping into a round, single loaf, as I did, place on a cookie sheet lightly greased and sprinkled with cornmeal. Let the loaves rise in a warm place for two hours.
Bake in a preheated 450-degree oven for 10 minutes. Then turn down the heat to 350 degrees and continue baking for 35 more minutes.
Remove the loaf to a rack and allow it to cool for at least 15 minutes before unmolding.