Invoice VOID Button; Would you like it?

[David Godfrey <..hidden..>]

Currently if you make a mistake entering an invoice (Vendor or Client) and post the invoice before you realise,
you have to manually find and edit the invoice, changing all QTY's to negative numbers, and any payment to a negative, edit the Invoice Number to show that it has been voided, and possibly add a comment to the notes field.
Then you can save the invoice as new.
At this point there may be nothing else to do (customer changed their mind before leaving store),
or you may have to reedit the original invoice, make corrections then once again Post as New.

I propose a two part solution to this.

First, add a RED "VOID" button to the Document. (if it is being edited)
  this would
    1. negate all QTY's and Payments,
    2. add VOID to the invoice number
    3. add a note "Voided by $username on $date at $time"
    4. Post the Invoice as NEW

Second, if it can be done without major modification to the code,
  add a RED "VOID and Raise" button to the Document. (if it is being edited)
    1. negate all QTY's and Payments,
    2. add VOID to the invoice number
    3. add a note "Voided by $username on $date at $time"
    4. Post the Invoice as NEW
    5. Reopen the Original Invoice for editing.

Things like AP and AR Transactions would still need to be manually voided and reraised.
Although I think the same method would work for them too.

The first part should be easy enough to implement, while the second may pose some interesting challenges.