I had filed the IT returns for FY 2009-10 (AY 2011-12) and I there is no tax balance to pay. But I had Loss in the mutual funds the same year which I did not declare in the IT returns (to carry forward)

As I read in the forums, If I have filed the IT returns within the validity period, I can submit any number of revised return forms. But at the same time I see the websites mentioning that the loss in that year cannot be carry forwarded.

I did not do any mutual fund transaction this year (FY 2011-12) and thus there is no capital gain.

My question is if I submit the revised IT returns :
1. Will I be able to carry forward this loss of FY 2010-11 to futher years ?
2. Do I need to pay any penality ? (NOTE: Only need is to declare losses)
3. If I cannot carry forward, do I really need to submit revised returns ? (I want to know what other problems could rise if I do not tell IT dept about my loss)?