sky ls3 conversion

I am converting a 09 sky with a e37 ecm. I see where a couple of places are taking the org ecm and reflashing it for the swap so the bcm will still communicate and all the cars controls will still function . I can not find any info on this. Does anyone know what they are doing to make this work? I know the easy way is to use a e67/t42 b ut I want to use all the fuctions of the bcm.
Below is a link

http://www.performanceautowerks.com/...oducts_id=1873

From what I understand the E37 and the E67 have the same architecture. So is it possable to flash a e67 os on the E37? Never have tried or heard of but they are making this work somehow.