Acetone will certainly remove it but I'm not sure about it 'softening' the top layer. I'm purely guessing here but it will probably dissolve the finish down to a certain depth, with the finish beneath that remaining hard. A bit like a layer of water on ice. There is no 'soft' ice layer in-between the hard ice and the water; it's either water or ice.

You can always try the acetone though.

Have you emailed Solarez yet, as they are the ones who will really know their product.

As the wipe-on version is best applied chilled, and you have been wiping it on rather than spraying (getting it thin enough to spray is why they suggest you warm it up a bit), you might want to have a go using it chilled. I don't know if there is any real difference between the wipe-on and spray-on versions in terms of additives to the main compound, or whether it's mainly just marketing with different application instructions e.g. cool/warm, but the safety data sheet implied it's 99-100% Polyol Acrylate.