NULL in source gets converted to Blanks in target

I am using Data Services to load data from the SQL server to  Teradata. For target columns of VARCHAR or CHAR data types in Teradata, if the corresponding source column value is NULL, the data is loaded into the target as a  blank field value instead of NULL. But for other datatypes like datetime or int, NULL in source is loaded as NULL in target. I am using the FASTLOAD bulk loader option in Data services to load data into teradata.

Should i change any setting in the data services config file to solve this problem?

Edited by: indumeena on May 31, 2011 9:54 PM