Issues in LSMW - Vendor Master

Dear Experts,

Am creating a LSMW for Vendor Master. The LSMW is working fine.

But the issue is,while creating vendor through LSMW-It is asking bank details as mandatory.

But if we create directly through XK01,the field is optional.

can anyone please share,why the system behaves like this?what i need to do make Bank details field optional in LSMW?

Thanks in advance..............