InfoPath Dev

It is a SP List that I altered the InfoPath for.  I think I figured out a solution.  I think Multi-selection boxes are useless in a list library and only useful in a form library.  I ended up using a LOOKUP column and ticked the box allowing multiples selections.  Now my form works as well the data entry from datasheet view ...

I have included a Multiple-Selection List Box in an InfoPath form for a List Library.  If I right click on the control I can see that the "Get choices from an external source" is selected and my external source is showing.    But if I right click on the field in the Fields list, my external choices are gone, ...

So what I need is a way to grab data from a multi-selection list box tool (which grabs values from a data connection to a SP list) and get the " ; " in between the values.  For this I am currently using this eval formula: eval(eval(RepeatingGroup, 'concat(my:Value, substring(";", 1, ...