While working with report viewer and Stored procedures which uses temporary variables
you might have got the problem of not getting schema in dataset. To resolve this issue use Table variables to return table instead of returning usine table varaibles
like select * from #temp

e.g of Table variable

Declare @x Table (ID bigint identity(1,1), Name varchar(50))

Insert into @x (Name) values('Satalaj More')

Select * from @x

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Table variables work similar to temporory variables you can get more details about temporory variable and

table variable at here http://www.codeproject.com/KB/database/SQP_performance.aspx

-Satalaj