debits, credits and reversals.

[Colin Scott]

>From time to time I need to reverse a transaction, for a number of 
possible reasons.   Gnucash insists that to make the reversing transaction 
I must use a debit amount to replace the credit, and a credit amount to 
replace the debit.  So far so good.  However, It seems to me that the 
purpose of the transaction it would be clearer if I were able to reverse 
the sign of the values rather than their colums - ie, enter a negative 
credit and a negative debit instead of a debit and a credit.

Is there some deep philosophical (or book-keeping!) reason why this is so, 
and that negative values are not permitted except as balances?  I have 
certainly been able to use negatives in other accounting systems I have 
used ...

Colin