Edit Button in Shopping cart

Dear Experts,

I got a requirement to make the edit button visible on approver level. I done it by enhancing the component /SAPSRM/WDC_UI_SC_OIF_CA and written code to make the EDIT button visible. I am able to see the edit button for approvers but when i click on the EDIT button the shopping cart is not changing to editable mode. Kindly guide me, did I miss any config level change?

Thanks & Regards

Arun.K.P