Hi,
I would also suggest looking at some of the function modules used inside the monitor to check for stock etc. Check this function group:
/SCWM/STOCK_OVERVIEW_MON
Has a list of FM that you can call to querry stock.
Regarding the AVL group you need to define what the users want to see. Since EWM in most cases uses two AVL GRPs, stock first is available in one (at receipt) then moves to the second during putaway.
Thanks,
Faical