Capital gain on equity derivative trading

I have gains in trading equity derivatives stock features in financial year 2012-13. approximately rs.40000/=

pl let me know how the derivative  gains are to be treated,and  how much tax to be paid. does this gain come under short term capital gain.I know that trading in equity derivatives thru recognised stock excahnge with certain conditions, are not treated as specultive..

can these gains be set off against long term capital loss arrived on sale of equity shares ,sold thru off market,i.e. not thru recognised stock market. on which STT not paid.

can these gains be set off against short term capital gains arrived on sale of equity shares sold thru recognised stock market which is STT suffered.

kindly clarify.