issue with BAPI_ACC_DOCUMENT_POST

Hi,

I am using BAPI BAPI_ACC_DOCUMENT_POST to post FI document. I am populating

obj_type = 'IDOC'

obj_key = 'TestBAPI'.

DOC_TYPE   =  'KR'

This is vendor invoice and document is getting created properly.

However when we try to reverse this using FB08 it is giving error 'Not possible to reverse the document in financial accounting'

I checked and created document has Ref Transaction has value 'IDOC' where as manually posted document has value 'BKPF'.

When i try to post using obj_type = 'BKPF', it is giving below error

How to post document with  obj_type = 'BKPF'

Thanks in advance.