SRM 7.0 Invoice posting issues, validation

Question

Hi  Experts ,
We are configuring SRM7.0 with ECC6 ( Ehp4) having Classic Scenario .
1. In Std SRM , we can post Invoice both ways
   With ref to PO
   W/o ref to PO.
We don't want to post Invoice w/o refernce to PO. How it can be stoped ? I want system should even, not allow user to post invoice w/o ref to PO ( Should give error).
2. We had NOT actiacted "Activate Direct Posting to G/L Accounts and Material Account" in ECC Invoice Config. But in SRM, If we post any invoice w.r.t. PO and add some extra line item, than system do not Stop me , and just give message that "Invoice 80000000112 is created, but not forwarded to Accounting " and its ststus shows "Waiting from preceeding document".
How it can be stoped ? I want system should even, not allow user to post invoice w/o ref to PO ( Should give error)?
3. We are using GR based IV in PO.
If for any PO , GR is not done
User tried to post the invoice in SRM, system gives error message that "Precessing document  req for invoice is not availble", but if I POST it , system proceeds it with green color message "Invoice 80000000113 is created, but not forwarded to Accounting " and its status shows "Waiting from preceeding document"
If PO Qty = 100, GR= 20, IR =100 Qty
System 1st give error Message
Line 1 : Qty too high ( Tol  Limit of 0.00 AUD exceeded)
Line 1 : Value too high ( Tol  Limit of 0.00 AUD exceeded)
And after that if user POST it, then system just do not Stop me , and just give message that "Invoice 80000000057 is created, but not forwarded to Accounting " and its status shows "To be Corrected Manually". How this can be stopped ?
I believe , by using DOC check or ITEM Check BADi this can be done , Can anyone suggest there is another way ?
Thanks
NAP

Answer 1

Thanks Ranjan,
1. No there is no any Portal Link for Invoice w/o PO. In the Portal for SRM BP, same single link displays from which we can post both Invoice w.ref to PO and w/o PO.
2. Since we do not want user to make mistake. System should stop him and do not allow if PO is not refered or IR Qty > GR Qty.
Do anyone have any inputs.
Thanks
NAP