Hi,
Can you check BTE 1820.
I have used this BTE 1820 for Debit balance check and also for due date selection.. may be this is useful in your case, as you also want to restrict the data at the proposal stage.
For document type selection, you can use free selection to restrict selection to only those document types which you have mentioned there.
Hope it helps..
Good Luck!
BR,
Kavita