payment - invoice connection

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not sure whether this is a bug or a new feature in 2.6
- I have a posted invoice and apply a payment to it
- then I need to change the invoice, so I have to unpost it
- once reposting there is no connection to the payment anymore (even though
the transaction still exist)

anyway to get this back (used 2.4 before and ther you always got the
payment bak on all reports, etc after a repost)