Hi Deepak,
FreeMASTER won't help much with such tasks as communication bus analysis/sniffing. It's main purpose is to monitor and control your embedded application variables. You could still be able to get some data going through FlexRay by copying the frames into a variable and display it in FreeMASTER UI, but that does not guarantee you the same accuracy as a dedicated analyser, because FreeMASTER may not read data from the target at the same rate, at which dataframes come from FlexRay.
An example of a task that would be a better fit for FreeMASTER is to monitor communication statistics (ex: number of frames send/received), but it would still require a piece a piece of logic, that gathers those statistics and stores them, implemented in the embedded application.
Regards,
Iulian