insert dimension measurment field on dimension line

I am trying to show primary units in decimal inches with period separator (1.5") and aternate dimension to be shown with a comma separator ([38,10 mm]) . But in autocad you cannot show different separators, just one separator type, either period or comma, not both. I have learned you can do somthing similar with a field. Now I am looking to do this with lisp. I would like to select the dimension, then the program would add a field as part of the dimension line, this field should be linked to the dimension and formatted to look like [38,10]. I saw some code by Lee Mac called c:dimf and it does about half of what i need, the next step would be to add the field to the same selected dimension. Decimal inch first with period separator then the field on right side shown with brackets and a comma separator. Please see attachted drawing for sample of a field on a dimension line.

AltDim.dwg