Steps to capture the excise in Dealer case is
1) Create a PO- use a tax code which has zero BED,ECS,SHCESS and applicable(4% ,12.5%) VAT ,Kindly note that the net price int PO should be all inclusive of excise duties as well
2) capture excise invoice in tcode J1IEX,tick the indicator MRP under miscellaneous TAB ,during which you have to change the excise base amount ,input the BED ,ECS ,SHECESS as mentioned in the vendor invoice.note that the sum of base amount bedecs+shecess= PO net value( excluding VAT)
3)In MIGO ,refer the excise invoice which was captured in step 2.and post the document.
4)In tcode J1IEX post the excise invoice
5)MIRO for the vendor