Internal Requisition in iProcurement

Dear all,

We need  to setup internal requisition in iprocurement , but the problem is while defining smart forms for internal requisition , I am unable to find the fields source and destination inventory og needed , can any one explain how to define setup steps for internal requisitions do we need any OAF customizations to achieve this functionality , how does iprocurement call different workflow while using internal requisition , at the  moment we are using AME for iProcurement , how the system  differentiates the two kind of workflow

for internal and purchasing when used with iprocurement ,  we are using 12.0.4 

Regards,

Chico