Forms :: Day Of Month Not Required To Be Visible

I have a table that records a list of dates using the first of the month in short date format (01/01/2011) and I have the following query

Code:

SELECT Format([dateworked],"mmm yyyy") AS Monthyear, Table_dateworked.dateworked
FROM Table_dateworked;

This query is the source for a combo box so it stores the actual date but the formatted date is visible.An additional complication (if it has to be) is that I have two combo boxes and I want to make sure the finish date is later than the start date, so I have a similar query which only returns later dates than the start date.

What I would like to do instead is to remove the combo box and to get the user to type in the month and the year in the "MMM YYYY" format, default the day to the first of the month and make it invisible.How difficult would this be? Would it be easier to enter the date in short format and change the format using the after update event?