Starting on very steep mountain with V60 automatic. Tip?

Hello, have a V60 D3 automatic Bj17. Are on vacation in a holiday house which is located on a very steep slope (>20%). The slope is graveled and comes up well. Problem is that the entrance to our house is secured with remote controlled roller gate. So start up slope, open gate and until I am up, the gate is half open. Unfortunately too slow so and further away the remote control does not reach. So has to wait short and then at 90 degrees angle again a small steep hill l high. Starting up is exciting every time, because I don’t get the power properly dosed and spin the VR on the gravel. Is coming from the lowlands, so with something so overwhelmed. Is there a trick, how I can make the more elegant, that I don’t slip in there every time with spinning tires? Thanks for tips!