Manual Tax Lines

Hi,

I couldn't update the existing Tax Rate/Tax Amount for the tax lines in a credit memo created against a Projects Invoice. Also, I am not able to add any new Tax lines to the CM.

- Query the Projects Invoice

- Menu-> Action-> credit

- Credit Tax only

- Update Tax Amount

- Save the record and re-query

- Changes made are gone

If I try to enter new tax line I get the error "Manual Tax Lines are not allowed"

However I can update and add tax lines for any credit memo that are created in the transaction screen (not against an existing invoice).