Is there any specific reason why we can\'t use SSIS in windows azure ?
SSIS isn't currently supported on SQL Azure, I'm not sure what is the background for the question, but I don't know if there is a need to seek a specific reason - there are still many technologies that are not (yet) supported on Azure but Microsoft is increasingly introducing more capabilities.
For example- SSRS was not available on Azure initially, but is now in CTP, and will be RTM in the near future; I don't think it's a question of if, but rather a question of when (but I'm sorry, I don't have an answer for that one)