Membership query

I have cleared CA final in May 2012 and have applied for membership and COP. I will join the office of my Principal (Sole Proprietary firm). But I am neither a paid assistant nor a partner in that firm. Can I sign audited the financial statements in the letterhead of the firm with my name and membership no (not designating as a partner)????? Else either the firm should either take me as a paid assistant or reconstitute the firm as a partnership firm????? Please help.....