Accessing GOS Functionality

Question

Could you please give me a code sample for how to use the following GOS methods?:
1)  CL_GOS_ATTACHMENT_QUERY -- should return a count of attachments, notes, etc for an object
2)  GOS_ATTACHMENT_LIST_POPUP -- popup the Attachment List Window (I think?)
I want to be able to add a button to the toolbar in FB03 that will appear if the object has an attachment and popup the attachment list when clicked on.  Where can I find out more documentation on GOS functions?
Thanks for your help.
Points will be credited for help.

Answer 1

For checking number of attachments
  i_object1-typeid = 'KNA1'.
  i_object1-catid  = 'BO'.
  i_object1-instid = docno.
  call method cl_gos_attachment_query=>count_for_object
    exporting
     is_object = i_object1
     ip_arl    = space
    receiving
     rt_stat   = i_stat1.
  read table i_stat1 into wa_stat1 index 1.
  if sy-subrc eq c_0.
     move wa_stat1-counter to v_attno1.
  endif.
For enabling a toolbar button in FB03 , you need to find a userexit or enhancement spot  to accomodate the PF status with an additional button on the basis of V_ATTNO1 (from above said variable)
a®