2023 F21 Tomcat , draining rear locker ballast pumps

[calgarymb]

I’m wondering if there is a way to drain my rear locker fat sacs from the touch screen , like I do for the bow ballast fat sacs. 
 

it seems I can fill only to 7:30 minutes for the rear bags but touch screen doesn’t offer option to “draining” them via the pumps. I only can drain them when I open the tanks as they drain into the tanks . 

for winterising , it would also be helpful so when I pour antifreeze into the fat sac, if I could activate pump for draining them, It would then draw the antifreeze in fat sac into the pumps and out the bottom of boat .