VI import limits data that can be imported

I have a VI job that imports in to a UDF associated with the IM_ProductLine table. 

One of the UDF's; "UDF_LIC_ROY_DUE" is a number masked to two (2) digits. It is intended to hold a number between 1 and 31, representing the day of the month payment is due.   

The *.csv source file holds the value of "..., 30,..."

The VI Import is bring in "3" instead of the desired "30".

On the Import Field Properties for that data element, I try to use the source substring field to start the import at position 2, but as soon as I enter the 2, the Length automatically changes to 1 and will not let me set it to a Length of 2.

Any thoughts?