customer master upload using LSMW direct input method - Issues

Hi,

i'm working on the customer master upload using LSMW Direct Input method

i was given 6 files i.e for KNA1, KNVV, KNB1 etc

how should i proceed?

should i create a structure for each of the files; like KNA1 as a header structure and the remaining structures in the next level to KNA1 structure?

but how the system will map between the 2 files say between KNA1 and KNVV ( which has got multiple records for each customer); what to do for this?

Also, we have some custom fields which should be populated.. i guess we can't see the fields in the structure which we get in the direct input method.. what do do in this case?

Any suggestions will be highly appreciated and assure you of full points

Thanks in advance

Shekhar