I have a Single Line Textbox in a Repeating Section, which has the Data Type set to Decimal.

I want to format the value entered in this control to 2 decimal places.
If I set the String Format for this control to "0.00", then once I submit the form, the value entered correctly formats to 2 decimal places - e.g. 123 returns as 123.00.
However, when I then look at this value in the Repeating Section XML, the formatting is not retained: the value 123.00 returns as 123 in the XML.

How do I format the value in the control to 2 decimal places so that the formatting is retained in the Repeating Section XML - e.g. 123 returns as 123.00 both in the form control and in the XML?