Hi Mayur,
when you print invoice, invoice must be send to CO, if not you can't print invoice. That's is check in a routine linkt to the NACE transaction.
In NACE transaction you could put a routine in the link between schema & output type. This routine for invoice must check your status "C"
But, that will never lock user to manually send the invoice. To do this, you have to modify the program that call the IDoc / Smartforms / ...
regards
Fred