SSRS returned row truncated in a dataset

Hi everyone, a few days ago I found an issue that I think was originated by the length of the report parameter, but I think that I found the real problem. I have a dataset which is must be filled with one simple row (xml type), the thing is that the xml returned was truncated and instead of return one simple row the dataset is had been filled with 3 rows because the xml is too long and it has been splitted in to many pieces. How can I obtain one simple row in my dataset? This situation has been a real headache and is a very urgent thing :'(

Thanks in advance!!!