I am testing this feature of DAS, trading from montage L2. If you right click in L2 > Config Level 2 the config window will open. In the column config, move ORDER to the right and it will show a buy button in every price level in the bid, and a sell button on every price level in the ask. You will be able to send limit orders typing # of shares and clicking the price level of your choice in the bid or the ask.
This is particularly useful in SSR stocks, rising devils or just to take profits in a patient way in congested price levels. An as these will be limit orders, you will be adding liquidity.