Hi,
As seen above, the best solution is to use class VMD_EI_API. check it in se24
I used it to create vendors and it works wonderfully.
This really acts like a BAPI.
If I remember well, you have to initialize the vendor with method INITIALIZE.
Fill your structure IS_MASTER_DATA, it contains every data you need to update.
HEADER Types VMDS_EI_HEADER
=> Contains the vendor number
CENTRAL_DATA Types VMDS_EI_CENTRAL_DATA
=> Contains most of the vendor data (LFA1)
COMPANY_DATA Types VMDS_EI_VMD_COMPANY
= > Contains most of the company data (LFB1)
PURCHASING_DATA Types VMDS_EI_VMD_PURCHASING
=> Contains most of the purchasing organization data (LFM1)
If you use specific fields, you simply need to had it to the includes.
Then call method MAINTAIN_BAPI with them.
Please check this question as answered if you think it is, else I would answer to your questions.
When I tried to find something on this subject I couldn't find anything usefull except this class name in the middle of nowhere, so I hope my search would help someone