Sorry, but this isn’t something that I’m going to be able to help you with. If this was something simple like getting a list of categories or a list of posts or something, I might be able to help you with, but where and how the someone gets and returns the values for this field is something that each person needs to work out. I don’t know much about the dynamic text extension plugin and I don’t use it very often, so I don’t know how it works or how you’d use it to fill the select values of this field.
Looking at the other question that you posted (I won’t answer there so that maybe someone else will help you) there isn’t any way to collect values from other input fields and supply them to the filter in this field, especially if you’re looking to get values entered into the form and not something that can be generated before the form is displayed. If the values are generated before the field is displayed then you would generate them the same way. There is not AJAX functionality in this plugin that can regenerate the selections after the fact. You might want to look at creating some JavaScript that will do this.
