Urgent :Store null date into table

[Blue Sky]

I have a field called dte which is a datetime type and allows null.
But I can't insert a null date into it. I found out that dte only stores "1/1/1900", but not null

.........
.........

drp = " " (I also tried drp = null, but it can't work)

sql = "Insert Into Cus_TBL Values " & _
"('" & Trim(txtID.Text) & "','" & _
Yr & "','" & drp & "')"

Please help me !
It's urgent !!!