Automatic generate the PO in extend classic scenario

HI ,expert :

I work in SRM7.0 and extend classic scenario.

requirement :

The employee create SC manually .If the SC is complete ,the following document PO will generate automaticlly .And if the SC is incomplete ,the purchaser can do "carry out sourcing ",and transfer the SC to RFX .

Q1 :

How can I set the "sourcing "-always carry out sourcing ,or nerver carry out sourcing ,Or carry out sourcing for item w/o SOS ?

Q2:

IF the PO generate automaticlly ,Can I chage it in SRM ,OR I must change it in ECC system ?

BR

Alex