For some custom requirement, we wanted to create a custom program to extend already existing vendor to new company code. We didn't want to go for BDC or IDOC. I knew about VMD_EI_API. I had used to create vendor from scratch. So for header data, company data and purchasing data, the task is 'I' (Insert/Create). But now for this extension, when I put header task as 'M'(Modify) and company data task as 'I' and purchasing data task as 'I', the method MAINTAIN_BAPI runs fine and does not return anything in defective message. I commit work at the end of program.
But when I am checking in LFB1/LFM1, there is no record for the new company code/Purchasing Org.
I followed lot of old posts & discussions -
for example - https://archive.sap.com/discussions/thread/3801942
But in my case, it is not working. There is no log in SLG1.
I am very sure there is no problem in data. I even created a test program and hardcoded the values which I put in XK01. In XK01, with same values, it works. But same data which I am passing through VMD_EI_API=>MAINTAIN_BAPI, there is no error message in return but then there is no record in LFB1/LFM1.