Organization accounting preferences

[Xavier Olivella]

Hi all,
 
I keep trying things about my other problem (not solved yet) and I
wonder a couple of things.
Which config is desirable in "Organization accounting preferences"?
 
The tax form for organization only have some examples from US, how can I
add my own?
If we choose the invoice sequence called "Restart on fiscal year" how
can I add some prefix or suffix in invoice number to differentiate each
year?
 
Thanks in advance.