Question regarding Default tax code in ME21N based on account assignment category

Dear Friends,

We are implementing SAP ( S4 HANA ).

I have a query regarding Default tax code to be populate in ME21N based on account assignment category for CAPEX OR OPEX

I know there is std sap config based on material indicator/Plant indicator/acct assignmnet indicator but my requirement is not fullfill by std config so

i tried to use exit

Exit_SAPLMEKO_002

INCLUDE: ZXMO6U15

But somehow it is not working.

Can you please suggest someother user exit?

Your early response would be highly appreciated.

Regards

Chandra Prakash