Invoices marked as paid

[Parminder Singh Chauhan]

Honestly, I never used gnucash before and tried to have a go. In
mandrakelinuxe 10.1  found gnucash version 1.8.9.
My situation is like that
we sends one or two invoices per week to three or four customers and receive
payments after 60 days. I created some invoices and posted them to account
receivable. Then  I processed payments in checking account. when I look at
 the invoices through find invoices command, I finds some invoices are marked
 as paid and some are not. I also find some payment received in receiveable
 account are splited in two or three payments and some of them are just
 fine.

Is there any way to hack program to manually tell gnucash that invoice is 
paid?  My main object of using this program is to track invoices agains 
payments.

By theway I unposted and posted invoices second third time as well and 
processed payments through business menus and as well as from find invoices 
window.
-- 
Parminder Singh Chauhan