I think I have found the answer for the part of the question. The ' Ã ' is the output record header and use to identify the table it has been unloaded from. Three values can be used for header (OBID,NONE or CONST). If you specify a header that can be used as a selection criteria in the WHEN clause.
My other part of the question is DB2 load Vs DSNTIAUL what are the pros and cons ?