saumik,
Here is the process i suggest
Assumption the stock still now available in plant is excise exempted .Because we are not giving any excise payment to vendor , There is no excise number , Excise registration etc etc.
As you have not taken credit to your i/p mat , you cant charge it to customer .
The challenge is , When you a goods receipt now after the Plant treated as Excisable plant .
How will you track the material from your already available stock ?
Solution -
Batch availability
Create a new Storage location (if 10 stores are there where your stock already available , make 20 and the newly created 10 Sl will be excisable)
Create new valuation type (Excisable val type)
This will resolve your current problem.
Future Challenge 1.
Now comes Phy Inv .
In system you can track with Val type for Excisable and excisable exempt But in physical store how will you manage ?
Solution
arrange new space in Storage location for all those new Excisable mat( most recommended)
Talk to your store manager and production ( he will have some suggestion and idea to track it separately)
Future Challenge
If you issue the Excise mat to production and make aprd out of it, it need to charrge the excise
and if the excise exempt material, its should not add your excise.
Truly recommend to consult with a FICO guy and FI user at senior level before you proceed.Give things in writing and get a confirmation mail .
mention the step by step process with details.
regards
manu