since now a days it has become mandatory to file income tax return with digital signature whose accounts need to be audited u/s. 44AB of the income tax act, my query is that suppose an individual having a turnover greater than 60 lacs for march 2011, need to submit return within 30th sep 2011 but the proprietor expired in mid august without applying for digital signature, now how to file the itr? please guide me through the process for filing the return in this case.