Display default date value 1899-12-31 to NULL in SSIS - please help!

Hi,
   I have a Excel source file with say, three columns - BirthDate,Place and Address.

In the loading table , their datatypes are date,varchar(50) and varchar(100) respectively.

The requirement is,
if the Birtdate is blank in the source then NULL should be displaced.
If Place and Address are blank, then blank should be diaplayed.

I tried 1) Checked the Retain NULL values option from the source file

Now, Both BirthDate is  diaplaying as NULL as required but Place is also displaying as NULL.

But as per the requirement, Place should be displayed as blank.

I tried 2) unchecked the Retain NULL values  option from the source file

Now, place is coming as blank  as required but birthdate is coming as 1899-12-31.

I tried 3) unchecked the Retain NULL values  and in the derived column created a derived column with expression isnull(Place)? "" : Place - this is working fine. Satisfied both of my requirements.

But  there are lot of varchar columns will be come in the future and so cant create Derived column for varchar columns.

So, my requirement is, how to convert default date value 1899-12-31  to NULL in the SSIS expression or changing some properties somewhere?