Display minutes as hours and minutes

To display minutes as hours and minutes in my report, I am using this format field formula:

local numbervar Hr := Truncate (CurrentFieldValue/60);

local numbervar Mn := Remainder (CurrentFieldValue, 60);

ToText (Hr,0) + ":" + ToText (Mn,0)

This formula is working great.  However, the results are 1:31 (1 hour and 31 minutes) and 1:7 (1 hour and 7 minutes).

Is there any way to edit the formula so 1 hour and 7 minutes shows up as 1:07?

Thanks for any help!