Hi Bashir, thank you for your answer.
That's not the problem. I think the problem is that I can't have two temporary tables for only one Data Provider when I'm using SRSTmpTblMarshaller.
I had solved this modifying the original table adding the new fields I need, and modifying as the Data Provider for filling it, as the Report itself for filtering data.
Anyway, I will be pleased if someone knows how to change it.
Thank to you all.