2.
It is mandotary for all aseesee to file ST-3 returns online using ACES. The last date for filling ST-3 return for the period from July 2012 to sept-2012 is 15/04/2013. The electronic version of the ST 3 Return for the period from July-2012 to sept-2012 is under development and is expected to be available on ACES around 25th March, 2013.
As per my information no alternative solution is given to the assessee. At least, you can keep the data ready as per paper format in Excel so that return can be filed at earliest upon availibility of electronic format in ACES.