extended classic scenario

Hi guys,

I am basically MM consultant and new to SRM. We are implementing extended classic scenario in SRM 5.0 I have following doubts

1) Do we need to configure enterprise structure also in SRM?

2) Do we need to configure release strategy for contracts/POs in SRM or it will flow from R/3

3) If we want to create contract/PO in R/3 also, can we create manually?