reg MB_MIGO_BADI

Hello guru,

here i am suffering from problem that in migo tcode when specific user enters particular vendor the GL associate with it which will be changed for that i have implemented the BADI but i can not understand how can i get the G/L for that if i got it can change in which field i got that is stored

suppose 001 G/L i got i have to change 100 now if i get it from any of field i can do it.

so plz help i u know proper ans.