Not true. I play with no time limit, and when you want to quit a sally battle, just his ESC and Quit Battle. There will be a prompt that has a message for loss, draw or victory. Something like:
- Are you sure you want to quit? You will lose this battle. (loss)
- Your sally has been successful. Do you want to quit? (draw)
- You have won this battle. Do you want to quit? (victory)
I've found that the game is a little fickle when deciding if you've drawn or lost. Sometimes you have to make sure to pull all of your forces back inside your gates or you may risk getting a loss. I don't know precisely what determines the victory/draw conditions for a sally, but it's not just how many kills you get. My suspicion is that you need to raise the balance of forces bar above the mid-point, but I'm not sure.
Does anyone else know what the victory/draw conditions are for a successful sally?