Zero Fill a Month and Day for an Auto-Fill Date

I created a drop down box for a required SelectMonth and SelectDay field within a required Date field (Year is hard coded as 2019). For Month and Day entries 1-9, Drop Down Box lists them as "01", "02" etc. up to 09. If selected, they appear with the Zero. In the Format, both fields are listed As None.

How can I use a drop down box for Month and Day with Zero Fill then re-use them in other attached documents as Month and Day exactly as shown in the Drop Down Box? Again, all Month and Day fields are formatted as None.