Problem in Service Contract

There is a 'loophole' in Service Module Version4SP3.

When i try to post a service invoice generated from a service contract, an error prompts
"Old open service ledger entries have been found for service contract C145000025. You must close them by posting the old sales invoices."

Here are what i did:-
1) Create a service contract, starting date 1/April/2009
2) Sign the contract, create sales invoice for April 09 - YES
3) Create sales invoice for May 09
4) Remove "Appl- to service ledger entry" at April service invoice line, leave "Service contract no." untouched
5) Post April service invoice
6) Post May's service invoice - error!

The reason why this error is encountered is because user has removed the 'link' from S/Invoice to S/Contract partially(service contract no. is not removed).
The system still record s/invoice as "posted" in contract header but in service ledger entry, it is consider as "open".

The only solution that i can think of is to "patch" the service ledger entry. i.e. to 'close' the service ledger entry programatically.

Is there any better way to solve this problem (without vendor's intervention)?