implementing back navigation memory in design studio 1.1

I'm new to Design studio 1.1, don't know if I have to do all this or just wait for next release or service pack .

im trying to implement  navigation memory so that with each forward step  the previous  drill down steps are remembered & user can back track the drill down. im using a filter panel & have a variable  list  for each dimension in a step

so if there are 5 dimensions D1,D2,D3,D4,D5 & I want to remember up to 5 steps then I  created  string variables list of  5X5=   V11...V15 , V21... V25 , V51..V55 & another variable called STEP

so every time user selects a bunch of filters in a  step all the filters get  saved  in the variables corresponding to the step

eg STEP =1  & Dim1 & Dim2 are assigned  values in FILTER Panel , then on APPLY variables  V11 & V12   get populated  & STEP gets incremented

my problem  is programming the "back track" widgets onselect event.( ive created listbox pop ups emulating context menus in Bex query)

if (STEP>0){

     if (STEP == 1){

          if (Convert.stringLength(""+V11)!= 0){/// im adding "" as I was getting script errors

           DS_1.setFilterExt("DIM1", V11);

           what else do I need to do     here

         }  

          if (Convert.stringLength(""+V12)!= 0)  {           

                DS_1.setFilterExt("DIM2", V12);

               what else do I need to do     here ?.

           }  ..........................................etc           .

}

     if (STEP == 2){

          if (Convert.stringLength(""+V21)!= 0) {

              DS_1.setFilterExt("DIM1", V21);

             what else do I need to do     here?

         }

          if (Convert.stringLength(""+V22)!= 0) {

             DS_1.setFilterExt("DIM2", V22);

           what else do I need to do     here}

......etc }

}  ..................... etc you get the point

STEP= STEP-1;   .

also need  HELP to disable LISTBOX element  if STEP =0

also need to note that  between step n1 & n2 the same DIM can  have modified  filters eg : in STEP1 DIM1 has filter values V11= A;B; in  STEP2 DIM1 has filter values  V21=C; along with other dimensions

also the filter panel  needs to remember the earlier step values assigned. currently out of the box that functionality is  shaky. the values don't appear immediately when the filter panel opens

any help will be greatly appreciated

Thanks

Prasad Badal