Non Recoverable Tax

Hello,

I'm trying to make non-recoverable tax working for ap invoices. I've read several setup documents, but I'm still in doubt if what I want to define is possible.

Here a few questions to start with.

1) Can a recovery rate be overwritten manually in AP? (where can I do this).

2) Or must recovery rates always we defined for use in AP?

3) Can calculated recovery and non-recovery amounts be overwritten manually?

4) Are recovery tax rules alway required to make non-recoverable tax possible?

Thanks in advance,
Arne