Sorry, wish I could be more helpful, but yo uare literally working on SUPER old technology. Going to a 2040 from a FAS 270 .. God, I don't want to be in your shoes.. Plus you are still running 7.2.x.. ugg..
But, if this needs to exist, you need to work through the compliance piece, are you running snaplock enterprise or complaince mode, Also, You can snapmirror do a non compliance volume and robocopy will work for your subset and then set your compliance up
My heart feels for you man...