how to run direct input method and BDC

my requirement is that i am having flat file in which having the fields to map with direct input method using

RFBIKR00.

and even the fields which are not having the mapping fields in RFBIKR00 like houseno,e-mail,comments in XK01.

how can i maintain the BDC for the fields are not having the mapping structure in RFBIKR00.

PLS HELP ME OUT ITS URGENT...