Problem Generating Report Through C#

Hi,
I have craated an interface for generating the rdl file through c# (User will select some fields for group and some for details and report will be generated accordingly). I am generating the XML for the rdl according to the schema. And the report is running fine in my local system where i am using sqlexpress but is not working in production. The problem is coming with the datasource as follows.

An error has occurred during report processing.
Cannot create a connection to data source 'SOP'.
Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection

I am using Integrated Authentication, below is the datasource code generated by c#

<DataSource Name="SOP">
<ConnectionProperties>
<IntegratedSecurity>true</IntegratedSecurity>
<ConnectString>Data Source=SIGMASQL;Initial Catalog=SOP</ConnectString>
<DataProvider>SQL</DataProvider>
</ConnectionProperties>
<rdataSourceID>36a274d3-f283-4ac9-9f26-401ddf14f733</rdataSourceID>
</DataSource>

When i am pasting the RDL xml to my BI project's Report it is giving preview properly, but after deployment it is not coming.
I have tried with SQL Authentication also by removing the IntegratedSqcurity element and changin g the connection string to add "sa" userid, but still it doesn't run and gives the same error and if i refresh the report with the refresh button of report viewer, it shows some Wrong String Format error.

When i am editing the dataset in the report designer(BI Project), the connection string is not storing password and username info in the xml of the rdl, i read somewhere that it stores these values in VS2005 and reporting service database with some encryption and don't keep in the xml. So it is seeming to me that i am not sending these credentials to reporting service while deployment through my c# code. Below is my deployment codebyte[] byteRDL;System.Text.UTF8Encoding encoder = new UTF8Encoding();

byteRDL = encoder.GetBytes(reportDefination);

Property[] rsProperty = new Property[10];

//Property property = new Property();Warning[] warnings;

warnings = rs.CreateReport(reportName, "/QuoteReports", true, byteRDL, null);

But i have no idea why it is not even running with Windows Authentication also.
I am in big trouble guys. Pls help. I have to show it to my client..