Do you have a user form by any chance?
If you have a form, then you can use the date picker control and put it on
the form. Its available from the additional controls. Right click on the tool
box and select additional controls, select the date  and time picker control.

Initially hide the date time picker control. You can put the textbox over
the datetimepikcer.

In the click event of the text box make the date time pciekr control
visible, and hide text box. When the user selects the date , assign the value
of the date time picker control to textbox and hide it.

Any way is this what you had in mind?

Hope this was helpful.

Anand.V.V.N