hi,
try to create a template for double-ms-surround recordings using the schoeps DMS-plugin (
http://www.schoeps.de/dmsplugin.html )
have 3 input channels ( M, S & B )and 6 outputs ( 5.1 ). between both needs to be the plugin.
i don't prefer cubase / nuendo ... but it is all so simple using them ( create 3 channel input, create 6 channel output, add plugin at the input ... bingo ) while in reaper it not that simple to do ... ( didn't found a solution yet )
hope reaper get soon some real multi-channel features too.
w.