Change FI doc.type for Credit Memo in MIRO

Hi everyone,

I'm trying to change document type (BLART) in FI document created through MIRO when a Credit Memo is made.

I'm using method HEADER_DEFAULT_SET of BADI ZMRM_HEADER_DEFAULT but nothing changes. This is my code:

   FIELD-SYMBOLS: <fs_rbkpv> TYPE mrm_rbkpv.

   DATA: c_rbkpv(15) TYPE c VALUE '(SAPLMR1M)RBKPV'.

   CASE sy-tcode.

     WHEN 'MIR7' OR 'MIRO'.

       ASSIGN (c_rbkpv) TO <fs_rbkpv>.

       <fs_rbkpv>-blart = 'KG'.

   ENDCASE.

Any advice?

Thanks a lot!