Binding data to dynamic download UI element

Hi,

One Upload UI element and the document uploaded is stored in custom table. Once it is uploaded and stored successfully the Upload Ui element is replaced by a download UI element. Till here I could do...

Now when I click on this download element I am getting a 'Null object Reference' error. Its because no data is bind to this element. How to bind the data in custom database to this UI element??? I need to bind the values to the following properties..Data,Mime type,text.

the method i used to create download element is :

CALL METHOD cl_wd_file_download=>new_file_download
EXPORTING
* activate_access_key =
* behaviour = E_BEHAVIOUR-AUTO
* bind_behaviour =
bind_data =
* bind_design =
* bind_enabled =
* bind_file_name = ls_tax_download-zfile_name
* bind_image_first =
* bind_image_height =
* bind_image_source =
* bind_image_width =
* bind_mime_type = ls_tax_download-zfile_type
* bind_target =
* bind_text = ls_tax_download-zfile_name
* bind_text_direction =
* bind_tooltip =
* bind_type =
* bind_visible =
* bind_wrapping =
* context_menu_behaviour = E_CONTEXT_MENU_BEHAVIOUR-INHERIT
* context_menu_id =
* data =
* design = E_DESIGN-STANDARD
enabled = 'X'
* file_name =
* id =
* image_first = 'X'
* image_height =
* image_source =
* image_width =
* mime_type =
* target =
text =
* text_direction = E_TEXT_DIRECTION-INHERIT
* tooltip =
* type = E_TYPE-NAVIGATION
* view =
* visible = E_VISIBLE-VISIBLE
* wrapping =
receiving
control = lr_download
.