I am new to this "baking hobby using a bread maker". I have faced the same challenge, and at this very moment am experimenting to find the best "trick" to avoid having unsightly impressions created by the machine paddlers; therefore, I would like to share with you what I have "come to know" basically through experimenting, and some confirmed through readings:
Basically the bread maker is used for making bread and cakes; for cakes the solution is simple and straight forward.. simply because the cake ingredients whence mixed they become in a semi fluid state; to remove the paddles before the baking cycle or just when it starts, you can simply do the following:
Use a kitchen hand-held mixer (egg whisker) with suitable design, and insert it in the pan so the large end would form something like a net around the bread maker paddle/s, and gently pull up. You should experiment with this with the bread maker (B/M) pan empty and the machine is turned off and unplugged.
As for breads.. I have experimented with removing the paddles at different times during the operation of the bread maker, but always before the baking cycle or when it had just started. I must say that I am still experimenting to find the absolute right moment of time to do so; and I believe its only logical to tackle this matter (and experiment) with the understanding that different B/M have different timing with regard to when best to remove the paddles so the bread will not be adversely affected; and actually today I came across this very interesting page referring to this specific point: