Form personalization - copy value from previus record

Dear all,

i have a requirement to copy GL_DATE value from previous record or first record in Receivables > Control > Autoinvoice > Interface Lines.

example :

no     Sales Order     GL Date

1          xx12               16-JAN-2015

2          xx13

3          xx14

4          xx15

5          xx16

for line 2-5, GL_DATE value are copied from previous GL_DATE field or GL_DATE field on first line. we cannot fill with SYSDATE because my company regulations are allowed backdate for GL_DATE.

i've been struggling to do that with personalization but have not found yet.

Regards,

Suryadi