Hi Sriram,
By saying "create SC from ECC", may I know you want to create SRM SC in ECC, or create ERP SC in ERP itself?
As far as I know, as of EHP 6 of ERP 6.0, Self-Service Procurement is available in MM to create ERP Shopping Cart. You may take a look at this on line help:https://help.sap.com/erp2005_ehp_06/helpdata/en/de/7657fbb8444476ac605da0aa043d14/frameset.htm
Hope I didn't misunderstand your question.
Regards,
Wendy