Dynamic DropDown is repeated on Dynamic Subform

Hi,

Scenario:

I am developing an offline interactive form.

In the form i have dynamic SubForm (add/delete button).

In the dynamic SubForm, i have:

   1 DropDown with ticked "Allow Custom Text Entry".

   1 button to connect to SAP web service and return the table for the DropDown binding.

For example, let's say the DropDown is for material.

Objective:

User can enter material description with wild card, press the button, SAP will return the list of materials. The dynamic binding will do the magic to generate the DropDown.

Issue:

For simplicity, let me explain the issue with example.

   1. User enter A* in the DropDown of the 1st subform and click the button. DropDown is generated with all material start with 'A'.

   2. User click add button, the 2nd subform is added.

   3. User enter B* in the DropDown of the 2nd subform and click the button. DropDown is generated with all material start with 'B'.

What happened after the 3rd step is: the DropDown in the 1st subform changed and now list all materials start with 'B', which is not what i want to achieve. I know the system behaves correctly because of the dynamic binding.

Kindly advise how to solve this.

Version:

SAP BASIS: 700 level 0023

Adobe LiveCycle Designer v8.1.2

Thanks in advance !!