can anybody plz tell me???

hey guys.. m gonna write final may exam.. my tranning got completed on 31st dec'10.. i've already sent  the form 108 but have not recieved my service certificate so far.. now i wanna fill exam form for may.. plz tell me whether any member can sign my form or it could be signed by principal only. do i have to attach any proof of completion if i got signed by any memeber.. if yes then what would be appropriate proof for that.