Hi Shweta,
i was also stuck at this position but finally i got the way out.
you should use the following code in your client and i am sure that it will work out for you.
UserTransaction utx = null;
utx = (UserTransaction)context.lookup("UserTransaction");
Now before you are calling that remote method
write
utx.begin();
and after you finish calling that method write
utx.commit();
Note : context is nothing but the instance of InitialContext
I hope it woks for u