I am convicted by trial court u/s 420,471 to get govt job by producing forged ST certificate. some office lapses went against me but the ST certificate itself is a big evidence that it was not a forged document. we filed appeal u/s 374(3) CRPC.My lawyers are saying that there is no chance to examine ST certificate by handwriting expert and forensic expert (to know the age of paper) now in appellate court. But I am sure that there will be some provisions for it. please give me idea how can i get examined the ST cetificate by forensic expert? under 391 CrPc?