StringList more or less would work only one way (so, modify index of stringlist from the graphic form by bind value -> from option). If You want to have a combobox element with a list which will then send Your pick to agent, try 2 options:
Option 1 (easy, but there is no central point for the list):
Just type in Your list into combobox elements (remember that first element has index 0)
then, add to the combobox Bind Behavior->From SelectedIndex on TextChanged event:
Option 2 (more advanced, but has central point for the list):
Use database table and connect it to combobox using ViznetDataBinder (so, select in the Task button (the top-right play button) use data bound items and attach to it Your valuemember and displaymember from viznetdatabinder) and then do bind behavior from but this time send Your valuemember (so most probably index number) to send it to Agent.
For more on databinders, just type in databinder into MAPS help or check this knowledge base for more, i.e.:
You can always create a dictionary in graphic form script and bind it as datasource to combobox.