Delphi 5 and running a DTS Package

I am having a problem with the user/password section of the code.

When I run the DTS from the code, it does not use the password I am
sending it - it is instead using NT authentication.  Since the people
that need to run this are not set up as users in SQL Server it fails.
Is there a switch I need to turn on/off somewhere?

Here is my code - when I run it it works perfectly.

  dtsZipCodeTaxImport := CoPackage.Create;

  sServerName := WideString('servername');
  sUserID := WideString('user');
  sPassword := WideString('password');
  sPackageName := WideString('dtsname');

  dtsZipCodeTaxImport.LoadFromSQLServer(sServerName, sUserID,
sPassword,
    DTSSQLStgFlag_Default, WideString(''), WideString(''),
WideString(''),
    sPackageName, pvarhost);

    try
    dtsZipCodeTaxImport.FailOnError := true;
    dtsZipCodeTaxImport.Execute;  

Any ideas?
Thanks
Susan