Maximum line item in settlement rule (need more than 999)

Hi All

Requirement is our user needs more than 999 distribution rules in an Internal order settlement rule

I have gone through the forum and find out one thread

http://scn.sap.com/thread/2053635

Above thread is explains, it has been done by some development

So how can I achieve this functionality by development

Thanks in advance and inputs will be rewarded

Vishnu