Hi Siddarth,
Please refer to note 900825. As per classic scenario commitments are not managed in sc in SRM. Commitments are accounted for in ECC at PO creation. If you want to have commitments at the sc level (as in PR in ECC) you would need the note 900825 (consulting note to implement commitment from SRM sc in ECC). Also recent 1373958 to contact sap consulting.
We have preffered to use reporting available in SRM and add some fields for our users. @ Month end they can see what is pending in SC in SRM not processed yet and account for as commitments.
best regards, hope its usefull,
FYI we are using the new SAP UI add on for SRM with Ariba if this can help or other questions,
Daniel 