ExcelBanter - ADO to SQL - smalldatetime problem

Excel 2002
MDAC 2.8
SQL Server 2000

I'm trying to test a stored prcedure by sending data to it from Excel.
There are three smalldatetime parameters that work fine if the Excel data is
formatted to display no time component. If the cell format includes the time
component, I get this error

-2147217833
Arithmetic overflow error converting expression to data type smalldatetime.

A little experimenting shows that ADO is sending the displayed value, not
the cell's actual value.

The table to which the stored procedure writes REQUIRES a time component for
2 of the columns, so I get a database error if the time portion isn't
included.

Anybody have any ideas how to push Excel data and time data into a
smalldatetime parameter?

Thanks
Duke