Hi Savin,
Please understand the custom solution is out of our support boundaries. I have included some links for you that may be helpful, including the features available to developers for Office 365. Perhaps some of the other users on this community will have experience useful to your issue. You may also want to post your question to the MSDN forums for a better response for custom solutions.
Here are links for your reference:
http://msdn.microsoft.com/en-us/library/ie/gg454740.aspx
http://msdn.microsoft.com/en-us/library/ie/gg454742.aspx
http://blogs.msdn.com/b/sharepointdesigner/archive/2008/06/20/data-source-issues-and-workarounds.aspx
http://msdn.microsoft.com/en-us/library/hh147180.aspx
Thanks,
Allen Qiu