Unrealized VAT and Credit Memos

fmhigue

I setup Unrealizaed VAT it seems to be working fine when posting a sales order. It created the following lines:

300000-4200 -Sales -465.07
256000-0000 - Tax -74.41
111000-0000 - Accts. Payables 539.49

When I paid the document and it worked fine too. It cancel the taxes as following:
256000-0000 - Tax 74.41
256001-0000 - Fiinal Tax 74.41

But then I created another invoice with the same items. But this time I did a Credit Memo. It worked really strange. Let me show the lines created

300000-4200 -Sales 465.07 - Perfect Cancel
256000-0000 - Tax 74.41 - Perfect Cancel
256000-0000 - Tax 74.41
256101-0000 - Final Tax -74.41
256000-0000 - Tax -74.41
256101-0000 - Final Tax 74.41
111000-0000 - Accs. Receivables -539.49 - Perfect Cancel

Any ideas.

Thank you in advance