Have you looked at [url=http://www.acrobatusers.com/tutorials/2007/js_list_combo_livecycle/]Programming List and Combo fields in Acrobat and LiveCycle forms Part 1[/url] and [url=http://www.acrobatusers.com/tutorials/2007/10/list_and_combo_in_lc/]Programming List and Combo fields in Acrobat and LiveCycle forms- Part 2[/url] by Thom Parker. Part 1 should provide you with everything you need. The only tricky part is the multi-demensional object.
George Kaiser