This method does work:
do a Google search to find the Emigrator VST.
On step 1 I turn the volume all the way up, it seems to boost the rear channel output.
I then take the single wav file output and encode with BeSweet and boost by a factor of 6 to 8 to increase the overall volume.
I have tried AC3Enc, Surcode, and Digigram enc… but I have found the above to be the best method. I have yet to find a good way to increase the volume through the rear channels, but this method does at least get about 40% through the rear. I wish there was an easier way… but I have yet to find one.