URGENT!!!Form No.16A &TDS !

hello all, can any1 guide me on following two Questions as being urgent?

1. IS it mandatory to quote PAN in all correspondence made between deductor & deductee even in invoice of sale of goods?

2. Can deductor give a form no. 16A in consolidation including payment/deduction on 31st March? if yes, then what is the last date to issue a Form No.16A? I want to know about current rules for financial year 2009-10 & not new amendments come last.